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MEET EURO NCAP CHILD PRESENCE DETECTION REQUIREMENTS WITH LOW-POWER 60-GHZ
MMWAVE RADAR SENSORS
January 4, 2023, 1:21 pm
Next How to optimize your automotive HVAC design in the growing HEV/EV market
0
0
Other Parts Discussed in Post: AWRL6432
Previously published on Electronic Products. Co-authored by Kishore Ramaiah.
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When shopping for new cars, safety-minded consumers can review New Car
Assessment Program (NCAP) ratings to see how cars compare NCAP ratings vary by
region, but Euro NCAP has been driving the initiative for child presence
detection inside cars as part of its roadmap.
Going into 2025 and beyond, only direct sensing solutions will garner NCAP
points, steering automakers away from indirect sensing alternatives – such as
door-opening logic, pressure capacitive sensing and unreliable weight sensing
solutions – toward approaches that use a single 60-GHz radar sensor.
60-GHz radar sensors deliver improved accuracy and are more cost-effective than
solutions such as weight sensors and camera-based alternatives, which can
struggle in challenging real-world lighting conditions. Sensors such as the
60-GHz AWRL6432 radar sensor can help you meet Euro NCAP design requirements by
enabling in-cabin sensing that can detect a child’s presence in a car, including
in the footwells, and enable very low system bill-of-materials costs.
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See our automotive 60-GHz radar demo video
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Clik here to view.Watch the demo video "Using 60-GHz radar sensors for
automotive child presence detection and intruder alerts" to learn how low-power
60-GHz mmWave radar sensors can deliver full-cabin automotive child presence
detection and intruder monitoring.
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Streamlining automotive child presence detection
Many companies have tested the potential to save children who are left in cars
unattended. For example, TI has performed several tests related to child
presence detection inside a two-row SUV with the AWRL6432. The tests included
the detection of a breathing doll, simulating a child, in a rear- or
forward-facing car seat or even laying in the footwell. Just one sensor was able
to detect the doll’s presence across two rows of seats, including the footwell
of both the first and second rows. Figure 1b shows how the radar sensor was
mounted overhead.
Test results, shown in Figure 1, demonstrate the sensor’s accuracy and ability
to detect a breathing doll left in an SUV. You can see that the doll placed in
the front footwell and in a rear-facing car seat installed in both the front
passenger seat and the second row driver’s side seat are all highlighted as
”detected,” even when the car’s engine is off.
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Figure 1: (a) Detection of a child (baby doll) in the front driver footwell,
(b)front passenger seat rear-facing, and (c) 2nd row driver-side rear-facing
inside SUV using the AWRL6432.
Harnessing the low-power capabilities of mmWave radar sensors
Euro NCAP requires child presence detection systems to run for a minimum of 15
minutes after the engine is turned off, ensuring that the sensor can scan,
detect and alert drivers if a child was left in the vehicle or gained unattended
access to the cabin.
Most radar sensors typically consume an average of hundreds of milliwatts, some
as high as 4 W. Newer 60-GHz millimeter wave (mmWave) sensors with low-power
architectures such as the AWRL6432 only consume an average of <10 mW over a
500-ms frame period. Minimizing chirp time and processing time can lead to
average power-optimized consumption as low as 2 mW, which helps automakers in
two ways:
1. Enabling highly accurate child presence detection without performance
trade-offs to save power on multiple trips.
2. Also facilitating intrusion detection with the same sensor, protecting
vehicles until the consumer’s next trip.
For intrusion detection capabilities, radar sensor must be able to continuously
run, monitor and accurately detect an intruder inside the vehicle for extended
periods of time.
Figure 2 shows that the AWRL6432 sensor is capable of proximity sensing,
detecting a person close to the car 1 m out. This is important for false flags
if, for example, someone was standing close to a car in a grocery store parking
lot loading their own groceries into their car. If a person were to actually
break into the car, breaking the proximity zone by sticking their hand through a
window, for example, the sensor would then alert owners that there is an
intruder.
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Figure 2: Intrusion detection simulation using the AWRL6432 (a) no living
presence near car, (b) person standing near the car, (c) person reaching into
car, sensor detecting an arm reaching through a car window.
Conclusion
Low-power 60-GHz radar devices such as the AWRL6432 enable automakers to support
child presence detection and intrusion detection while also helping meet
developing NCAP requirements. The AWRL6432 sensor’s low-power capability makes
it a good fit for electric vehicles, which have strict power budgets.
Implementing these capabilities with a single chip saves space and cost, helping
automakers incorporate these important safety features even on low-end models.
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HOW TO OPTIMIZE YOUR AUTOMOTIVE HVAC DESIGN IN THE GROWING HEV/EV MARKET
February 6, 2023, 7:00 am
Next How to optimize size and power consumption in LEO satellites with FDAs
Previous Meet Euro NCAP child presence detection requirements with low-power
60-GHz mmWave radar sensors
0
0
Other Parts Discussed in Post: TMS320F2800157-Q1
Co-authored by Kevin Stauder.
With the continued worldwide growth of hybrid electric vehicles (HEVs) and
electric vehicles (EVs), now more than ever, automotive developers are
innovating to stay ahead of the game. While differentiating HEV/EV powertrain
systems has traditionally been a key focus area, market leaders now cannot
afford to neglect differentiating their HEV/EV thermal management or heating,
ventilation and air-conditioning (HVAC) systems. Thermal management systems
consume the second most power in HEV/EVs (only behind powertrain systems) –
directly impacting drive range.
For decades, the internal combustion engine (ICE) has run vehicles and their
HVAC systems. In HEV/EVs, the size or even the absence of an ICE requires the
introduction of two additional components that play a role in an HVAC system:
* A brushless-DC (BLDC) motor to rotate the AC compressor, instead of the
engine doing so.
* A positive temperature coefficient (PTC) heater (or alternatively, a heat
pump) to heat the coolant, rather than the engine heating the coolant. In the
case of heat pumps, battery thermal management moves heat from the battery to
the cabin. Integration of the heat pump ultimately results in lower weight,
longer drive times and lower cost.
See Figure 1.
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Figure 1: The heating and cooling system in an HEV and EV
In this article, we’ll overview the design challenges associated with these
electronic HVAC applications, and discuss how real-time control performance,
scalability and cost can help address those challenges.
Reliable real-time control performance
High startup torque, high efficiency, low audible noise and low electromagnetic
interference (EMI) are the primary features in market-leading e-compressor
systems.
Let’s review the most important elements of HVAC performance, and why it’s
important to consider them:
* High startup torque: Systems with high inertia such as e-compressors require
high startup torque in order to run the compressor motor at the preferred
speed as quickly as possible, ultimately increasing the end-user experience
with the HVAC system.
* High efficiency: Other than a HEV/EV powertrain system, an e-compressor
system consumes the most power in EV/HEVs: around 5 kW. As a result, any
power savings through efficiency results in a longer driving range, which is
a concern for HEV/EV developers and consumers.
* Low audible noise and low EMI: In ICE vehicles, the engine is already audible
such that any noise coming from the HVAC system is minuscule by comparison.
But EVs and HEVs are susceptible to audible noise that stands out in an
otherwise quiet vehicle without engines. HEVs and EVs are also susceptible to
EMI from the BLDC motor and electronics needed for the e-compressor. The
e-compressor components in HEVs and EVs should not add any type of noise that
would disturb the existing system or the consumer driving experience.
* While the quality of e-compressor products are directly affected by the
system’s real-time control performance, traditional PTC heaters can fully
function without it, and designers lean primarily on cost to differentiate
these products. A PTC heater measures and controls the current flowing
through the system (with a single resistor), which ultimately controls the
in-cabin temperature.
* Heat pumps do indeed rely on strong real-time control performance, given the
integration of multiple motors on a single system. System and microcontroller
(MCU) architectures play an important role in enabling efficient and
cost-effective control of an integrated heat-pump system.
The block diagram in Figure 2 shows how the architecture and peripherals of TI’s
C2000 real-time MCUs can enable a heat-pump system through multimotor control.
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Figure 2: A heat-pump system controlled by a C2000 real-time MCU
Scalability
Given evolving trends and varying requirements from automotive original
equipment manufacturers worldwide, the ability to leverage a compatible platform
to scale across different application requirements is a priority. A
platform-based approach to an automotive HVAC compressor, PTC heater and
heat-pump design helps significantly reduce time to development and development
costs. For MCUs specifically, a wide range of options on package type, pin
count, flash memory, temperature, functional safety (Automotive Safety Integrity
Level B), cybersecurity, communication interfaces and cost are vital to enabling
a scalable platform for automotive HVAC designers.
Cost
System bill of materials, development resources and time to market are all
significant costs for automotive HVAC developers. Cost-effective components
(including the MCU), the ability to leverage a scalable platform and reference
designs help address these concerns.
TI’s High-Voltage EV/HEV E-Compressor Motor Control Reference Design is a
high-voltage, 5-kW reference design built for EV/HEV e-compressor applications
that’s controlled by the C2000 TMS320F2800157-Q1 real-time MCU. This reference
design showcases solutions to some HEV/EV e-compressor design challenges in
performance, scalability and cost.
See this reference design in action here: EV HVAC eCompressor motor control
Conclusion
HEV and EV adoption builds over the coming decades, so will the use of
electronic solutions for HVAC control. The automotive HVAC subsystems in these
vehicles require components that bring forth design challenges such as reliable
real-time control, scalability and cost. With the help of C2000 real-time MCUs
and reference solutions, you can smoothly navigate the move from ICE to HEV and
EV HVAC systems.
Additional resources
* For information on other subsystems and details about trends in heating and
cooling control modules in 48-V, 400-V or 800-V HEVs and EVs, see the white
paper, “How to design heating and cooling systems for EVs and HEVs.”
* Read about the C2000 F280015x Real-Time Microcontrollers.
* F280015x tool folder
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HOW TO OPTIMIZE SIZE AND POWER CONSUMPTION IN LEO SATELLITES WITH FDAS
February 6, 2023, 7:30 am
Next 5 converter topologies for integrating solar energy and energy storage
systems
Previous How to optimize your automotive HVAC design in the growing HEV/EV
market
0
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Other Parts Discussed in Post: LMH5485-SEP
Size and power consumption are two of the key design aspects for circuits used
in low Earth orbit (LEO) satellites. These systems require components that are:
* Radiation tolerant, to ensure proper operation in orbit. The operation of LEO
satellites in an environment without the protection of the earth’s atmosphere
subjects electronics to radiation and possible damage. Radiation-tolerant
components are less likely to be affected negatively by radiation.
* Small in size, to minimize board space. Size and their corresponding weight
in satellites are at a premium because lighter weights reduce overall launch
costs. Small electronic components can minimize the size of circuit boards
used in satellites.
* Low power, to reduce required battery weights and solar array size. Most
satellites are powered with solar arrays and batteries that affect the weight
of the system. Using electronic components that minimize power consumption
will reduce the overall size of the satellite’s battery and solar array, thus
reducing the weight of the system and, again, the cost to launch the
satellite into orbit.
Addressing design challenges with FDAs
Many analog-to-digital converters (ADCs) for LEO satellite systems have fully
differential inputs to help improve dynamic range and take advantage of the
fidelity improvements of differential signals. To drive the input of
differential ADCs, it is best to choose a fully differential amplifier (FDA)
that you can use with either differential or single-ended signals. Several
sensors do provide a single-ended signal that can be efficiently converted to a
fully differential signal. And while it is possible to convert a single-ended
signal to a differential signal by using two separate operational amplifiers,
FDAs offer smaller size, lower power, lower noise and an overall improved
dynamic range.
Figure 1 shows an FDA configured to convert a single-ended signal to a fully
differential signal in order to drive the inputs of a fully differential ADC.
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Figure 1: TI’s LMH5485-SEP FDA driving a fully differential ADC
Reducing noise to improve performance
Using a single FDA architecture to drive an ADC will provide 1/√2 lower noise
for the same power when compared to using a pair of single-ended operational
amplifiers. For example, an operational amplifier with an input voltage noise of
3 nV√Hz will have a total input voltage noise of 3 ´ √2 nV/√Hz in a dual
operational amplifier circuit. Some FDAs, such as the LMH5485-SEP amplifier,
feature a common-mode output Vocm pin to set the output common-mode voltage of
the amplifier to perfectly match the expected ADC input common-mode voltage.
Many ADCs include a common-mode voltage pin designed to connect to the Vocm pin.
You can also leave the Vocm pin on the amplifier floating if your intended
common-mode voltage is at the midpoint of the supplies.
Meeting mission radiation requirements
FDAs used in satellite systems also need to meet the radiation requirements of
the mission. The 850-MHz LMH5485-SEP FDA is radiation tolerant, with a total
ionizing dose assured up to 30 krad. The device is also single-event latch-up
immune to a linear energy transfer of –43 MeV-cm2/mg. The LMH5485-SEP is in a
small 3.0-mm-by-3.0-mm very thin shrink small-outline package package, shown in
Figure 2, and meets TI’s space-enhanced plastic (SEP) qualification. You can
learn more about SEP products from TI in the article “How Space-Enhanced Plastic
Devices Address Challenges in Low-Earth Orbit Applications.”
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Figure 2: LMH5485-SEP package drawing top view
Designers of LEO satellite signal chains face many challenges when selecting
components for their systems. The LMH5485-SEP FDA is one component in an
expanding portfolio that enables next-generation LEO satellites to achieve
greater performance at smaller sizes and lower power. The LMH5485-SEP achieves
radiation tolerance and small size while also providing low-noise performance to
achieve the maximum dynamic range and minimize total harmonic distortion for
differential analog signal chains. Take a look at the Additional Resources
section to learn more about other SEP products from TI, and how to optimize
signal-chain design with FDAs.
Additional resources
* Check out these application notes:
* “Reduce the Risk in Low-Earth Orbit Missions with Space Enhanced Plastic
Products.”
* “Maximizing Signal Chain Distortion Performance Using High Speed
Amplifiers.”
* Learn more about TI's portfolio of space-grade devices with the “TI Space
Products Guide.”
* Watch the TI Precision Labs video series about FDAs.
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5 CONVERTER TOPOLOGIES FOR INTEGRATING SOLAR ENERGY AND ENERGY STORAGE SYSTEMS
February 27, 2023, 9:29 am
Next How to achieve precise motion control in industrial drives
Previous How to optimize size and power consumption in LEO satellites with FDAs
0
0
Other Parts Discussed in Post: TIDA-01606, TIDA-010210
With energy storage systems prices becoming more affordable and electricity
prices going up, the demand for renewable energy sources is increasing. Many
residences now use a combined solar energy generation and battery energy storage
system to make energy available when solar power is not sufficient to support
demand. Figure 1 illustrates a residential use case and Figure 2 shows how a
typical solar inverter system can be integrated with an energy storage system.
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Figure 1: A residential solar energy generation and energy storage system
installation
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Figure 2: A typical solar inverter system with an energy storage system
In the best-case scenario, this type of system has highly efficient power
management components for AC/DC and DC/DC conversion and high power density
(with the smallest possible solution size) that are highly reliable (with the
lowest losses) and enable fast time to market. Those requirements are not always
achievable at the same time, however, and you will need to make trade-offs on
the best power-conversion topologies for these subblocks.
What existing power topologies for AC/DC and DC/DC buck and boost power
converters have in common are half bridges or converter branches that run
interleaved, either to increase power levels in a DC/DC converter or to achieve
three-phase operation in an AC/DC inverter or power factor correction stage by
placing three branches running in 120-degree phase shifts. Figure 3 shows
simplified schematics of five power topologies.
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Figure 3: Power topologies for half-bridge and branch equivalent
* Topology No. 1: In the two-level converter topology, pulse-width modulation
(PWM) signals are applied complementary (with a dead-time delay to avoid
shoot-through because of overlapping switching signals) to power devices Q1
and Q2. For the positive sine wave at the output, the duty cycle applied is
>50% at Q1. For the negative sine wave at the output, Q2 has a >50% duty
cycle. It is a simple concept to control the output power, but output signals
before the line filter have a full bus voltage swing, which requires a larger
filter to reduce electromagnetic interference. The ripple frequency into the
filter is the PWM frequency, which affects the size of the filter.
Three-level topologies allow the use of smaller passive components and have
lower EMI compared to two-level converters. There are four three-level
topologies:
* Topology No. 2: The T-type topology is named for the way that the transistors
are arranged around the neutral point (VN). Q1 and Q2 connect between the DC
link, and Q3 and Q4 are in series with VN. The ripple frequency seen by the
filter is equal to the PWM frequency applied to switches Q1 through Q4. This
defines the size of the filter components to achieve the required low total
harmonic distortion at the AC line frequency. Q1 and Q2 see the full bus
voltage and need to be rated at 1,200 V for an 800-V DC-link voltage in the
system. Since Q3 and Q4 connect to VN, they see only half the bus voltage and
can be rated at 600 V in an 800-V DC-link voltage system, which saves costs
on this converter type. See the 10-kW, Bidirectional Three-Phase Three-Level
(T-Type) Inverter and PFC Reference Design.
* Topology No. 3: In the active neutral point clamped (ANPC) converter
topology, VN connects with active switches Q5 and Q6 and sets VN in the
middle between the DC-link voltage. Like the T-type converter, the ripple
frequency seen by the filter is equal to the PWM frequency defining the size
of the AC line filter. What’s nice about this architecture is that all
switches can be rated at half the maximum DC-link voltage; in an 800-V
system, you can use 600-V rated switches, which positively impacts cost. When
turning off this converter, it’s important to limit all voltages across each
switch to half the DC-link voltage. In other words, the control
microcontroller (MCU) needs to handle the shutdown sequencing. TI’s
TMS320F280049 and other devices in the C2000 product family have
configurable logic that allows the realization of shutdown logic in hardware
to offload software tasks for the MCU. See the 11-kW, Bidirectional,
Three-Phase ANPC Based on GaN Reference Design.
* Topology No. 4: The neutral point clamped (NPC) converter topology is derived
from the ANPC topology. Here, VN connects through diodes D5 and D6 and sets
VN in the middle between the DC-link voltage. The output ripple frequency
seen by the filter is equal to the PWM frequency defining the size of the AC
line filter. Like the ANPC topology, all switches can be rated at half the
maximum DC-link voltage, but instead of two more switches, there are two fast
diodes. The NPC topology’s slightly lower cost compared to the ANPC topology
comes at the expense of slightly lower efficiency. The requirements for
shutdown sequencing are also identical to the ANPC topology. It is easy to
derive an NPC topology from the ANPC reference design mentioned above.
* Topology No. 5: The flying capacitor topology already tells you what’s
happening in this converter; a capacitor connects to the switch nodes of the
stacked half bridges realized by Q1 and Q2 and Q3 and Q4. The voltage across
the capacitor is limited to half the DC-link voltage and shifts periodically
between V+/V–; power transfers when shifted. This topology uses all switches
during the positive and negative sine wave. In this topology, the output
ripple frequency seen by the filter is twice the PWM frequency given each
cycle shift of the flying capacitor, resulting in a smaller-sized AC line
filter. Again, all switches can be rated at half the maximum DC-link voltage,
which positively impacts cost.
Table 1 lists the benefits and challenges of the different topologies.
2L
TIDA-01606 in 2L
T-Type 3L
TIDA-01606
ANPC
TIDA-010210
NPC 3L
derived from ANPC
FC3L
Flying capacitor 3L
Benefits
* Simple control scheme
* 2 switches only
* 2 PWM
* Easy control scheme
* Q3/Q4 see 1/2 VDC
* Better EMI than 2L
* fRIPPLE = fPWM
* Good efficiency
* All switches see 1/2 VDC
* Better EMI than 2L
* Lower cost than ANPC
* All switches see 1/2 VDC
* Better EMI than 2L
* fRIPPLE = fPWM
* 4 PWM
* Highest efficiency
* Only 4 HF FETs (& 1Cap)
* fRIPPLE = 2 x fPWM
* Smallest magnetics
* Lowest EMI
Challenges
* Q1/Q2 see full VDC
* High EMI for bigger fPWM
* Passives are biggest
* Q1/Q2 see full VDC
* 4 PWM
* More complex control scheme
* Shutdown sequencing critical
* 6 PWM
* Lower efficiency than ANPC
* More complex control
* Shutdown sequencing critical
* Initial charging of flying capacitor
* Shutdown sequencing critical
Table 1: The benefits and challenges of different converter topologies
All four three-level topologies have clear advantages on power density (with the
smallest possible solution size), highly reliable operation, and fast time to
market over traditional two-level converters. Using wide band-gap devices and
high-performance MCUs increase these advantages even further, at a comparable
cost.
Additional resources
* Learn more about how you can accelerate your development of solar energy
systems.
* Check out the Bidirectional, Dual Active Bridge Reference Design for Level 3
Electric Vehicle Charging Stations.
* Discover our battery management and power conversion technology for energy
storage systems.
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HOW TO ACHIEVE PRECISE MOTION CONTROL IN INDUSTRIAL DRIVES
March 7, 2023, 1:02 pm
Next 4 key current-sensing design trends that are powering electrification
Previous 5 converter topologies for integrating solar energy and energy storage
systems
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0
When riding in an elevator, I’m sure you expect a smooth and safe ride from one
floor to the next. In an elevator drive, precise motion control enables the
elevator to stop at specified positions and to slow down to a full stop
smoothly. A lack...(read more)Image may be NSFW.
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4 KEY CURRENT-SENSING DESIGN TRENDS THAT ARE POWERING ELECTRIFICATION
February 21, 2023, 10:22 am
Next 13 reasons to start using Power Stage Designer
Previous How to achieve precise motion control in industrial drives
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Other Parts Discussed in Post: TMCS1100, INA301, INA226, INA228, INA232, INA253
Among all of the buzzwords to describe the increased electrification of our
world, one term should stand out more: current sensing. Few of the innovations
you hear about in solar power arrays, electric vehicle (EV) charging stations or
robotics would be possible if current-sensing technology wasn’t reliable,
accurate and easy to design with.
In this article, I’ll address four key design trends that have emerged from the
growth of electrified applications and the current-sensing technologies intended
to address them: higher system voltages, increased system protection, telemetry
monitoring and reduced form factors. Overall, current sensors are monitoring a
vital parameter, current, in an electrical system and this allows for a system
to operate as efficiency as possible in a safe range.
Support for higher system voltages through current sensing
As efficiency requirements continue to become more stringent system voltages are
increasing as a result to help drive efficiencies. With higher system voltages
the amount of current that is delivered to a load can be decreased to create an
equivalent amount of power, based on Ohm’s Law, which helps reduce I2R losses in
a system. Higher voltages make it more efficient to pass large amounts of power
across a system because the current range is lower, generating less heat in
stages such as AC/DC or DC/DC power inverters.
The EV charger shown in Figure 1 is routing power off the grid, which could be
at voltage levels such as 120 VAC, 240 VAC, 230 VAC (one phase) or 400 VAC
(three phase). The typical EV charger routes AC power from a grid to an EV
onboard charger, which converts the power to DC and delivers charge to the
batteries.
In a DC fast charger, AC power goes into the EV charger from a grid, is
converted from AC to DC within the charger, and delivers voltages as high as 920
VDC to the batteries for faster charging. Stepping up to higher voltage levels
and keeping similar current levels makes it possible for more power to pass
directly into the batteries, making for quicker and more efficient charging.
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Figure 1: EV charger
Current sensors help increase system efficiency in EV chargers in and can be
used in multiple locations throughout the system. These sensors can be used in
the AC line inputs, which monitor current in order to adjust reactive power into
the system on the front end. Another is after the power factor control loop and
secondary DC/DC, either on the positive or negative node of the system; this
configuration monitors for faults.
There is also a location between the primary DC/DC and secondary DC/DC, where
current sensing from differential amplifiers be used for flux balancing. In
addition, it’s essential to use isolated current sensors like the AMCS1100 or
TMCS1100 to protect the system and humans interacting with EV chargers
Increased system protection
Electrification also increases the need for system protection which ensures that
a system reacts promptly to an event outside the safe operating area to avoid
damage to the semiconductor and other sensitive content. In most systems, some
form of system protection ensures that the system operates as intended. For
example, if the robots shown in Figure 2 pick up an unusually heavy item, there
may be a significant current spike in the motors.
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Figure 2: Industrial robots
A current spike may indicate that a load is beyond the robot’s capability, which
could potentially damage the content in the system or the physical robotic arm.
A current-sensing device with an integrated comparator would see the peak
current, perhaps beyond the safe operating area of the system, rush into the
electric motors. The INA301 with integrated overcurrent comparator could react
as quickly as <1 µS and set an alert, which may cause the system to shut down.
This is similar to a point-of-load measurement, where shunt-based sensors like
the INA228 and INA226 ultra-precise bidirectional current sense amplifiers can
monitor current flow and voltage-levels through a particular node to ensure that
the node remains in its safe operating area.
Enabling telemetry monitoring
As applications become more electrified, the requirements for monitoring
increase to track both consumption for energy ratings and better predictive
maintenance events.
An example of monitoring or telemetry monitoring for predictive maintenance is
by data logging the current and voltage levels going through the cooling fans in
rack server systems. Using a device such as the INA232 will data log the fan’s
power consumption. Data logging enables the system to alert technicians that the
fans may be acting erratically or nearing the end of its life.
Leveraging a digital power monitor is an appropriate style of device for this
use-case, since it takes in both bus voltage and current flow information.
Digital power monitor ICs do arithmetic onboard to calculate power, charge and
energy and transmits this information (plus the bus voltage and current-flow
data) through I2C or serial peripheral interface. Doing the arithmetic on-chip
offloads processes from the CPU or microcontroller, so processing resources can
be used to handle other tasks more effectively. This is especially important in
systems, where the CPU or microprocessor are handled many tasks.
Reduced form factors
As more applications include more electronic components or are needing to fit in
smaller spaces, there is a greater need to reduce the size of the components or
increase the number of features per unit to help reduce overall board area. Many
systems, such as smartphones and robotics systems, are size-constrained and
require a constant reduction in size and increased feature sets.
Smaller current-sensing devices allow designers to increase the amount of
monitoring throughout or to reduce the system’s overall size. Both cases could
be advantageous depending on the overall system parameters – reducing the size
of integrated circuits (ICs) or increasing the number of features per unit both
result in increased feature densities, enabling powerful personal electronics,
onboard chargers and small collaborative robot motor-drive systems.
Leveraging ultra-small ICs or highly featured chips can pave the way to smaller
systems. For example, chip packaging options such as a wafer-chip scale package
(WCSP) or an INA253 with an integrated shunt enables the designer to shrink the
size of their system without sacrificing performance or features.
Conclusion
With a better understanding of these trends and the ICs that help support them,
you can meet your specific high-voltage design challenges and enable reliability
and safety by monitoring current measurements to ensure that the system is
operating in a safe operating area.
Additional resources
* Read the application note, “Design Considerations for Current Sensing in DC
EV Charging Applications,” to learn more about current-sensing designs.
* See the application brief, “Current Sensing in Collaborative and Industrial
Robotic Arms.”
* Check out the Analog Design Journal article, “System Telemetry: What, Why and
How?”
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13 REASONS TO START USING POWER STAGE DESIGNER
March 10, 2023, 2:53 pm
Next Using vibration monitoring, Edge AI and SPE/PoDL for predictive maintenance
Previous 4 key current-sensing design trends that are powering electrification
0
0
For more than a decade, TI’s Power Stage Designer tool has been a great design
aid for electrical engineers when calculating the currents and voltages of
different power-supply topologies. I believe it is an easy tool to start a new
power-supply design, because it executes all calculations in real time, and you
get direct feedback.
Our latest version of Power Stage Designer includes a new topology and two new
design functions on top of its existing set of features that will help you
further accelerate your design time for developing power supplies.
The new tool contains a field-effect transistor (FET) losses calculator, a
current-sharing calculator for parallel capacitors, an AC/DC bulk capacitor
calculator, a resistor-capacitor (RC) snubber calculator for damping ringing
across rectifiers, a resistor-capacitor-diode (RCD) snubber calculator for
flyback converters, an output-voltage resistor-divider calculator, dynamic
analog and digital output-voltage scaling calculators, a unit converter, a Bode
plotting tool for loop compensation, a load-step calculator, and a filter
designer. Let’s look at each of these 13 features in detail.
No. 1: FET losses calculator
With this tool you can easily compare different FETs that are either operating
as a main switch or as a synchronous rectifier. The minimum, maximum and
root-mean-square (RMS) current values, FET drain-to-source voltage and switching
frequency will transfer from the chosen topology window. The tool can also help
you assess the total metal-oxide semiconductor field-effect transistor (MOSFET)
losses of synchronous converters after you’ve chosen applicable MOSFETs for the
main switch and synchronous rectifier. Figure 1 shows the FET losses calculator
window.
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Figure 1: FET losses calculator window
No. 2: Current-sharing calculator
When paralleling different kinds of capacitors at the input or output of a power
converter, the capacitors experience different amounts of RMS current, depending
on their impedance. With Power Stage Designer, you can estimate the current
stress for up to three parallel capacitors based on a first harmonic impedance
model.
No. 3: AC/DC bulk capacitor calculator
AC/DC converters typically have a bulk capacitor behind the input rectifier to
provide a quasi-constant input voltage to the power stage and power-management
controller. Power Stage Designer will suggest the bulk capacitance based on
different input parameters.
No. 4: RC snubber calculator for rectifiers
In power supplies, ringing across rectifiers can be a major issue if you need to
pass electromagnetic interference (EMI) testing. There are different methods to
deal with this problem, and implementing an RC snubber network is an easy
solution that might keep you from having to redesign your printed circuit board
(PCB) layout. Our tool gives you an easy way to determine the starting values
for your RC snubber network.
No. 5: RCD snubber calculator for flyback converters
Due to parasitics such as transformer leakage inductance, flyback converters can
experience voltage overshoot and ringing at the switching node. The easiest way
to reduce the ringing and to achieve damping of the overshoot is to implement an
RCD snubber circuit in parallel with the primary inductance of your flyback
converter. Power Stage Designer can help you choose starting values for the
snubber resistor and capacitor.
No. 6: Output-voltage resistor divider calculator
It is now possible to easily calculate the output-voltage feedback divider for
your power supply based on the output voltage, reference voltage and high- or
low-side resistance, including tolerances.
No. 7: Dynamic analog output-voltage scaling calculator
For some applications, the output voltage of a power converter needs to be
adjustable in a certain output-voltage range. You can accomplish this by feeding
a variable analog output voltage with a third resistor to the output-voltage
resistor divider. Power Stage Designer helps you find the values for the
resistances needed based on the chosen output-voltage range, maximum adjusting
voltage, reference voltage and top feedback resistance.
No. 8: Dynamic digital output voltage scaling calculator
It’s also possible to adjust the output voltage of your power supply by
paralleling multiple resistor/signal MOSFET combinations with the low-side
feedback resistor. By enabling and disabling the MOSFETs with a microcontroller,
it’s as if you’ve “programmed” different output voltages to the power supply.
Power Stage Designer will assist you in choosing the resistance values for the
feedback circuit.
No. 9: Unit converter
Power Stage Designer includes a little helper that converts different
power-supply parameters, such as gain to factor or imperial to International
System of Units, and vice versa.
No. 10: Loop calculator
The loop calculator displays Bode plots of the open- and closed-loop transfer
functions for the voltage-mode control buck, and five different current-mode
control topologies: buck, boost, inverting buck-boost, forward and flyback. You
can use five different compensation networks for closing the loop. Figure 2
shows the Power Stage Designer loop calculator window.
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Figure 2: Power Stage Designer loop calculator window
No. 11: Load-step calculator
With the load-step calculator, you can determine the required minimum output
capacitance for voltage-mode and current-mode-controlled converters to stay
within output-voltage regulation requirements. Take care when using this tool
with devices that leverage an internal compensation network, as the degrees of
freedom for choosing external components are limited with those kinds of
devices.
No. 12: Filter designer
The filter designer helps you design properly damped differential mode π-filters
for power supplies. The tool not only shows the Bode plots of the filter and
damping network, but also the graphs of the undamped and damped filter
impedance. With this information, it is possible to simultaneously determine
whether the filter provides sufficient signal attenuation and stability with
your chosen damping components. The filter designer will provide a very good
starting point, but to meet EMI specifications with a finished PCB, factors such
as PCB layout and component parasitics will have a significant impact on the
filter’s final performance.
No. 13: New topologies
* Our Power Stage Designer tool supports a total of 21 topologies, including
the four newest ones, the series capacitor buck converter
* Quasi-resonant/frequency-modulated flyback converter
* Inductor-inductor-capacitor (LLC) half-bridge converter
Inductor-inductor-capacitor (LLC) full-bridge converter. See Figure 3.
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Figure 3: Topology window of the LLC full-bridge converter
Power Stage Designer can make your life as a power-supply designer a little bit
easier.
For the equations and assumptions behind the new toolbox, see the “Power Stage
Designer User’s Guide.”
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USING VIBRATION MONITORING, EDGE AI AND SPE/PODL FOR PREDICTIVE MAINTENANCE
March 10, 2023, 5:02 pm
Next How Arm Cortex-M0+ MCUs optimize general-purpose processing, sensing and
control
Previous 13 reasons to start using Power Stage Designer
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0
Other Parts Discussed in Post: ADS127L11, AM2434, DP83TD510EFactory production
lines, manufacturing robots (see Figure 1) and wind turbines can unexpectedly
break down due to hardware failures that are very expensive to repair. Some of
these failures...(read more)Image may be NSFW.
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HOW ARM CORTEX-M0+ MCUS OPTIMIZE GENERAL-PURPOSE PROCESSING, SENSING AND CONTROL
March 8, 2023, 2:43 pm
Next How vision processors are expanding edge AI capabilities in video doorbell
and smart retail designs
Previous Using vibration monitoring, Edge AI and SPE/PoDL for predictive
maintenance
0
0
Other Parts Discussed in Post: MSPM0G3507
Microcontrollers (MCUs) in embedded systems are the equivalent of air traffic
control in a busy airport. MCUs sense their operating environment, take actions
based on those observations, and communicate with related systems. They manage
and control signals in an almost endless list of electronics, from digital
thermometers to smoke detectors to heating, ventilation and air-conditioning
motors.
Embedded designers need more flexibility during the design process to maintain a
system’s affordability and longevity. With currently available MCU portfolios,
designers are limited in how much hardware and code they can reuse across
current and future designs, and have limited computing, integrated analog and
packaging options. This limited flexibility often means that designers must
source MCUs from multiple manufacturers and spend additional time reprogramming
to meet the unique needs of each design, adding to development costs as well as
overall system cost and complexity.
The MSPM0 Arm® Cortex®-M0+ MCUs help solve these challenges by giving designers
more options, more design flexibility, and more intuitive software and tools. In
this article, I’ll explore what “more” really means in these contexts, and the
potential applications these MCUs unlock in terms of a wider range of integrated
analog options and processing capabilities.
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See MSPM0 MCUs in action at embedded world 2023
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Clik here to view.At embedded world in Nuremberg, Germany, March 14-16, visitors
to TI’s booth can see how MSPM0 MCUs can increase system efficiency and
processing and sensing capabilities. See ti.com/embeddedworld for more
information.
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More computing options
While the Arm Cortex-M0+ brought 32-bit computing capability to 8- and 16-bit
applications, designers are still looking for as much computing performance as
possible, including more software abstraction layers to enable code reuse and
longevity, the introduction of more analytics into algorithms with ultra-low
latency requirements, and the inclusion of more security.
MSPM0 MCU options for computing start from a 32-MHz Arm Cortex-M0+ central
processing unit (CPU) for simple applications and scale up to an 80-MHz CPU with
hardware-accelerated math functions, including acceleration for divide, square
root, multiply-accumulate and trigonometry (sine, cosine, arctangent of x,
arctangent of y/x).
With 80 MHz of computing power at two flash wait states, MSPM0 G-series MCUs,
like the MSPM0G3507, make it possible to implement low-cost MCUs into
applications such as:
* * Sensorless field-oriented control (FOC) motor-drive applications running at
greater than 30 kHz with lower control loop latency due to math
acceleration (example applications shown in Figure 1).
* Polyphase energy metering computation in grid infrastructures.
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Figure 1: example FOC motor-drive applications ( cordless power drill and home
appliances)
More integrated analog
Leveraging the MSPM0 MCUs’ integrated building blocks with flexible,
programmable on-chip connections – including successive approximation register
(SAR) analog-to-digital converters (ADCs), comparators and digital-to-analog
converters – can help improve the accuracy of sensing circuits. These building
blocks also include zero-drift, chopper-stabilized, programmable-gain
operational amplifiers with zero crossover distortion. Integrated transimpedance
amplifiers have ultra-low input bias current (150 pA) for implementing
photodiode circuits.
Reducing the input offset as an error source in low-cost sensing applications
makes it possible to apply a higher sensor signal gain while maintaining low
residual input offset errors across temperature, improving accuracy in:
* Power delivery applications such as battery charging and gauging.
* Monitoring and real-time control applications such as brushed DC and
brushless DC motor drives in appliances and power and garden tools.
* Medical monitoring signal chains including blood pressure monitors, pulse
oximeters and thermometers
* Building automation applications including smoke detectors and passive
infrared sensors, as shown in this demonstration video:
www.youtube.com/watch
The integrated SAR ADC supports monotonic 12-bit operation at up to 4 MSPS and
14-bit operation at up to 250 kSPS, with available simultaneous sampling for the
synchronized measurement of two signals. This functionality enables energy
monitoring in residential and enterprise applications, with simultaneous 14-bit
sampling of mains voltage and current, and high-speed low-latency sampling (250
ns) in motor drives such as compressors, pumps and fans.
Conclusion
Adding and improving features in cost-sensitive embedded systems is limited by
the sensing accuracy and computing capabilities of the MCUs that fit a
designer’s budget. And as more designers take a platform software development
approach, applying one software framework across many applications, it’s more
important than ever to develop on top of a portfolio of MCUs with scalable
features in order to ensure that every product uses the most cost-optimized MCU
with the necessary sensing and processing features. With modern MCU portfolios,
designers can add new features without adding cost – or keep the feature set
they have and reduce cost – while also developing scalable software that can be
reused in future designs.
Additional resources:
Read our series application briefs on how MSPM0 MCUs streamline designs in a
range of applications:
* Optimizing Field Sensor and Transmitter Applications With MSPM0 MCUs
* BLDC/PMSM Control Using Sensorless FOC Algorithm Based on MSPM0 MCUs
* Increasing Flexibility in Your Battery Management Designs With a Low-Cost
MSPM0 MCUs
* Build Scalability in Cordless Power and Garden Tools Using Low-Cost MSPM0
MCUs
* Designing Single- and Three-Axis Selfie Sticks With MSPM0 MCUs
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HOW VISION PROCESSORS ARE EXPANDING EDGE AI CAPABILITIES IN VIDEO DOORBELL AND
SMART RETAIL DESIGNS
March 15, 2023, 8:00 am
Next How a stand-alone active EMI filter IC shrinks common-mode filter size
Previous How Arm Cortex-M0+ MCUs optimize general-purpose processing, sensing
and control
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Other Parts Discussed in Post: AM62A3, AM62A7-Q1, AM62A3-Q1, AM62A7
With the trendiness of the term “edge AI” or talk of “having more intelligence
at the network edge,” it’s easy to lose sight of the benefits of having more
local, real-time processing that doesn’t rely on cloud-based resources to run
artificial intelligence (AI) models. By enabling the electronics we interact
with daily to make decisions in the real world based on AI models, we can
increase their responsiveness, safety and overall efficiency.
Of course, some AI-powered systems will likely always need cloud-based
resources. It is possible to greatly enhance many low-power applications,
specifically those with one to two cameras, with processing capabilities such as
people and object classification, anomaly detection and human pose estimation.
Implementing these capabilities in low-power applications can be challenging,
however, because of cost constraints as well the amount of power needed for this
level of processing.
Newer Arm® Cortex®-based vision processors such as the AM62A processor family
help designers expand vision and AI processing capabilities in applications
ranging from video doorbells to smart retail.
Let’s look at these applications in more depth to understand what expanded
vision and AI capabilities can enable.
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Making the future of embedded possible for edge AI
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Clik here to view.Watch the video "Making the future of embedded possible for
edge AI" to learn how TI enables advanced AI analytics and real-time
responsiveness in edge AI applications.
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AI cameras in video doorbells
In video doorbells and home security systems (as shown in Figure 1), any delay
in response to a theft or person identification, even for a millisecond, could
make a difference in preventing loss of life or property.
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Figure 1: Demonstration of people and object recognition running on a video
doorbell
By analyzing real-time video data locally, video doorbells can respond faster
and more reliably, with fewer false positives and no need for network
connectivity. But power and size constraints have traditionally limited the
level of AI processing necessary to achieve this real-time responsiveness.
The AM62A family, which includes the AM62A3, AM62A7, AM62A3-Q1 and AM62A7-Q1, is
designed to operate at 2 to 3 W, in a form factor small enough for use in
compact video doorbell enclosures. Video doorbell designers can implement higher
levels of human and object detection in their designs by leveraging the 1 to 2
teraoperations per second of AI processing in AM62A processors. Read the
technical white paper, “Edge AI Smart Cameras Using Energy-Efficient
AM62A Processor” to learn more about implementing AI processing in video
doorbells.
AI cameras in smart retail
Smart retail, also known as “grab-and-go retail,” is a new shopping experience
where customers select their purchases and then leave the store without having
to pay a cashier – it’s all handled automatically.
The vision-based systems managing this experience rely on
object-detection-derived AI models as well as barcode scanners to identify what
items customers put in their baskets and ultimately purchase when they leave the
store (as shown in Figure 2).
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Figure 2: AI camera using AI model to monitor customer activity in a smart
retail store
Smart retail applications can decrease response times during transactions and
increase data security by processing data locally. In particular for data
security, running AI models locally doesn’t require a network connection to
cloud resources – limiting the potential for unauthorized access of that data
since it is not being transmitted externally.
Similar to video doorbells, power consumption is a primary design challenge for
smart retail AI cameras, especially considering high-frame-rate video analysis.
The energy-efficient, highly integrated system-on-a-chip architecture of AM62A
processors unlocks the local AI processing capabilities of smart retail cameras.
These processors, through their integrated AI hardware accelerators, enable
objection classification, anomaly detection, orientation detection and barcode
identification – even on nonstandard surfaces such as fruits and vegetables.
Conclusion
More intelligence at the edge means more real-time responsiveness and reliable
human-machine interaction. While I only focused on two applications in this
article, the list of electronics that can benefit from locally run AI data
models grows daily. Highly capable, highly integrated vision processors are
making this transformation possible, and our world smarter.
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HOW A STAND-ALONE ACTIVE EMI FILTER IC SHRINKS COMMON-MODE FILTER SIZE
March 19, 2023, 8:06 am
Next TI extends support of Amazon Sidewalk to improve connectivity between
homes, neighborhoods and cities
Previous How vision processors are expanding edge AI capabilities in video
doorbell and smart retail designs
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Other Parts Discussed in Post: TPSF12C3-Q1, TPSF12C1-Q1
Automotive on-board chargers and server power supplies are highly constrained
system environments where power density is a primary metric. It’s important to
reduce the volume of the electromagnetic interference (EMI) filter components so
that the solution can fit into demanding form factors.
Common-mode (CM) filters for these and other high-density applications often
limit the total Y-capacitance – related to touch-current safety requirements –
and thus require large-sized CM chokes to achieve a target corner frequency or
filter attenuation characteristic. The result is a compromised passive filter
design with bulky, heavy and expensive CM chokes that dominate the overall
filter size.
With advances in passive components lagging behind high-speed power
semiconductor devices as well as circuit topologies, the volume of the passive
filter is one of the limiting factors for increasing power density. Practical
filter implementations can occupy as much as 30% of the total volume of a power
solution, as shown in Figure 1.
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Figure 1: A conventional single-phase passive EMI filter in a 3.3-kW totem-pole
power factor correction reference design
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Reduce system size, weight and cost
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Clik here to view.Learn more about our power-supply filter ICs.
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Active EMI filter (AEF) circuits enable more compact filter solutions for
next-generation power-management systems. Space-constrained applications can use
active power-supply filter integrated circuits (ICs) to reduce the size of
magnetic components and the overall filter. Additional benefits of an AEF
include lower component power losses for better thermal management and higher
reliability, reduced coupling between components within a confined space, easier
mechanical and packaging design, and lower costs.
Figures 2 and 3 are schematics of single-phase and three-phase filter circuits,
respectively, where an active solution replaces a traditional passive design.
The single-phase TPSF12C1-Q1 and three-phase TPSF12C3-Q1 AEF ICs, positioned
between the CM chokes, provide a lower-impedance shunt path for CM currents. As
illustrated, the active solution has CM chokes LCM1 and LCM2 with much lower
inductance relative to the same components in the passive filter.
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Figure 2: Single-phase passive EMI filter (top) and corresponding AEF circuit
with lower CM choke inductances (bottom)
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Figure 3: Three-phase passive EMI filter (top) and corresponding AEF circuit
with lower CM choke inductances (bottom)
AEFs
With Y-rated sense and injection capacitors connected to the AC lines, the
circuits aim to reduce the total filter volume yet maintain low values of the
line-frequency leakage current to chassis ground. This is possible by using an
active circuit that shapes the frequency response of the injection capacitor –
effectively increasing its value for high frequencies. In turn, the amplified
injection capacitance over the frequency range of interest for EMI mitigation
will lower CM choke inductances relative to the values of a passive filter with
comparable attenuation.
The circuit advantages using an AEF are:
* A simpler filter structure with a wide operating frequency range and high
stability margins (calculated using the common-mode AEF quickstart calculator
tool).
* A reduced CM choke size with lower volume, weight and cost. This also enables
much lower copper losses and better high-frequency attenuation performance
from reduced choke self-parasitics.
* No additional magnetic components – the AEF circuit only uses Y-rated sense
and injection capacitors, with no impact to peak touch current during a fault
condition.
* Enhanced safety using a low-voltage AEF IC referenced to chassis ground.
* A stand-alone IC implementation that offers flexibility in terms of placement
near the filter components.
* Immunity to line voltage surges to help meet International Electrotechnical
Commission 61000-4-5.
The X-capacitor(s) placed between the two CM chokes in Figures 2 and 3 provide a
low-impedance path between the power lines from a CM standpoint, typically up to
low-megahertz frequencies. This allows current injection onto one power line,
usually neutral, using only one injection capacitor. If the three-phase filter
is a three-wire system without a neutral, the SENSE4 pin of the TPSF12C3-Q1 ties
to ground and the injection capacitor couples through a starpoint connection of
the X-capacitors.
Practical AEF implementation
Figure 4 shows a practical AEF implementation suitable for the converter in
Figure 1. Using the TPSF12C1-Q1 single-phase AEF IC achieves CM noise
attenuation.
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Figure 4: Single-phase filter evaluation board with the AEF rated at 10 A
Figure 5 shows EMI results with the AEF disabled and enabled.
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Figure 5: European Standard 55032 Class B EMI results with the AEF disabled and
enabled
As evident in Figure 5, an AEF provides up to 30 dB of CM noise attenuation in
the low-frequency range (100 kHz to 3 MHz), which enables a filter using two
2-mH nanocrystalline chokes to achieve CM attenuation performance equivalent to
a passive filter design with two 12-mH chokes. To make a fair comparison, these
chokes come from the same component family (made by Würth Elektronik) with a
similar core material. Table 1 captures the applicable CM-choke parameters for
the passive and active designs, and Figure 6 highlights the volume, footprint,
weight and cost savings.
Filter design
CM choke part number
Qty
LCM1, LCM2
(mH)
RDCR(mΩ)
Size
(L × W × H, mm)
Total mass (g)
Total power loss
(W) at 10 A, 25°C
Passive
7448051012
2
12
15
23 × 34 × 33
72
6.0
Active
7448031002
2
2
6
17 × 23 × 25
20
2.4
Table 1: CM choke parameters for the passive and active filter solutions
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Figure 6: Footprint, volume, weight and cost reductions enabled by an AEF (a);
choke size comparison (b)
The AEF in this example achieves a 60% total copper loss reduction at 10 A
(neglecting the winding resistance increase from the temperature rise), which
implies lower component operating temperatures and improved reliability.
Conclusion
It’s challenging to achieve a compact and efficient design for the EMI filter
stage in high-density switching regulators, particularly for automotive and
industrial applications where solution size and cost are such priorities.
Practical results from an active filter solution to suppress the measured CM
noise signature indicate a significant volumetric reduction of the CM choke
components when benchmarked against an equivalent passive-only filter design.
Additional resources:
* Watch a video on active EMI filtering: Single- and three-phase active EMI
filter ICs mitigate common-mode EMI, save space and reduce cost.
* Review these white papers:
* “How active EMI power-supply filter ICs mitigate common-mode emissions and
increase power density in single- and three-phase power systems.”
* “An overview of conducted EMI specifications for power supplies.”
* For more details about the example in Figure 1, showing a conventional filter
design, see the High efficiency GaN CCM totem pole bridgeless Power Factor
Correction (PFC) reference design.
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TI EXTENDS SUPPORT OF AMAZON SIDEWALK TO IMPROVE CONNECTIVITY BETWEEN HOMES,
NEIGHBORHOODS AND CITIES
March 27, 2023, 8:45 pm
Next Top 3 ways to reduce audible noise in motion control applications
Previous How a stand-alone active EMI filter IC shrinks common-mode filter size
0
0
Many of us have experienced the wave of innovation inside our homes. Lights,
thermostats, appliances and locks are wirelessly connected. We have sensors for
motion, temperature, light, water leaks, and air quality – even for keeping
track of ou...(read more)Image may be NSFW.
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TOP 3 WAYS TO REDUCE AUDIBLE NOISE IN MOTION CONTROL APPLICATIONS
March 29, 2023, 2:41 pm
Next Addressing 3 power design challenges for corner radar systems
Previous TI extends support of Amazon Sidewalk to improve connectivity between
homes, neighborhoods and cities
0
0
Other Parts Discussed in Post: MCF8315A, MCF8316A, MCT8316AWith the emergence of
open-concept floor plans for homes and offices and the shift to hybrid electric
vehicles and electric vehicles, demand for quieter and more efficient motor
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ADDRESSING 3 POWER DESIGN CHALLENGES FOR CORNER RADAR SYSTEMS
April 6, 2023, 11:31 am
Next How little-known capabilities of Wi-Fi®︎ 6 help connect IoT devices with
confidence
Previous Top 3 ways to reduce audible noise in motion control applications
0
0
Other Parts Discussed in Post: LP87745-Q1, AWR2944
Co-authored by Abby Kainer
In the past decade, radar-sensing technology began replacing traditional
automotive-sensing modalities given its many advantages – which include
long-range detection, higher resolution and increased accuracy – for the
implementation of driver safety features, autonomous driving and advanced driver
assistance systems.
Radar technology directly measures the distance and radial velocity of oncoming
objects in any weather condition, including heavy rain, snow and bright
sunlight, thus making it a good technology for meeting New Car Assessment
Program requirements. As an effect of the increasing automotive radar market,
corner radar technology has quickly evolved.
Corner radars, placed at the two front corners and two rear corners on a
vehicle, sense output object data sent over low-bandwidth networks such as
Controller Area Network-Flexible Data Rate (CAN-FD) for the radar to process
directly. Corner radars aid in applications such as lane-change and
cross-traffic assistance, blind-spot detection, collision avoidance, pedestrian
detection, and distance warnings.
Designing a reliable corner radar application can be challenging, however,
especially when designing the power supply, since radar sensors typically
require specific noise and ripple levels, power capabilities, and thermal
dissipation to avoid affecting radio-frequency (RF) performance.
As we see it, there are three power-supply design challenges for corner radar
applications:
* The size of the power supply. A physically smaller power supply provides
greater power density and efficiency, offering you additional flexibility to
add more components to your design. Smart corner radar applications need a
smaller solution size given the limited space available in the corners of a
vehicle. A smaller power-supply size will also reduce overall system costs
while providing the same amount of power.
* The low ripple and noise specifications of radar sensors. Ripple directly
impacts the output voltage accuracy and noise level of the power supply,
which in turn affects the system’s overall RF. You could use second-stage
inductor-capacitor (LC) filters or low-noise low-dropout regulators (LDOs) to
help suppress noise spurs and ripple, but these components typically
compromise the power supply’s size, temperature and overall cost.
* The temperature of the power supply. As radar power supplies get smaller, the
heat generated per unit area increases. High temperatures can compromise the
integrity and life span of the power supply. If the radar chip overheats, the
speed of its operation can slow down or, in extreme cases, shut down the
entire system. For smart corner radars specifically, high temperatures
compromise the radar’s ability to measure the distance and radial velocity of
oncoming objects.
How a PMIC can help resolve power-supply challenges
Power-management integrated circuits (PMICs) can address the challenge of
achieving power density with a reduced solution size and simplified power
architecture when compared to a discrete implementation. PMICs that have
built-in sequencing can help monitor temperature levels and meet all Automotive
Safety Integrity Levels.
One approach is to use a combination of three low-noise buck converters and a
5-V boost converter PMIC for radar monolithic microwave ICs. The LP87745-Q1a
small-size PMIC designed for radar sensors.
The DC/DC switching of the LP87745-Q1 helps reduce overall cost, reduces noise
spurs, lowers ripple amplitude and enables a switching frequency (fsw) of 17.6
MHz, which provides two main benefits:
* You can eliminate the second-stage LC filter on each supply rail. Because the
high fsw is greater than radar technology’s intermediate frequency, there is
no need for the filters.
* A high fsw creates a lower ripple amplitude and reduces noise spurs, while
making it easier to control noise levels.
With the elimination of the external LC filters and LDOs, the LP87745-Q1 will
have lower levels of thermal dissipation that will not affect the RF performance
of the radar chipset. The temperature levels of the LP87745-Q1 manage the
thermal dissipation levels of the power supply, preserving the integrity of the
radar chip.
As illustrated in Figure 1, the LP87745-Q1 supports a 5-V rail for CAN-FD-based
radar chipsets such as the AWR2944.
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Figure 1: The LP87745-Q1 powering the AWR2944 radar chip for corner radar
applications
Conclusion
It is important to address power-supply challenges in order to have the most
efficient radar application, and to protect drivers and passengers. The
LP87745-Q1 helps support ASIL C functional safety systems; the elimination of
additional voltage monitors helps make it easier to meet functional safety
requirements at a system level. The LP87745-Q1’s novel feature set helps solve
power-supply design challenges for corner radars, with the potential for use in
front, in-cabin and cascaded radar designs.
Additional resources
* Read the technical article, “What ADAS Engineers Need to Know About the New
NCAP Requirements for Radar.”
* Download the LP87745-Q1 data sheet.
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HOW LITTLE-KNOWN CAPABILITIES OF WI-FI®︎ 6 HELP CONNECT IOT DEVICES WITH
CONFIDENCE
April 18, 2023, 4:00 am
Next Decrease factory downtime in 24-VDC power distribution with advanced load
diagnostics
Previous Addressing 3 power design challenges for corner radar systems
0
0
Other Parts Discussed in Post: CC3301
Wi-Fi® is increasingly available and even expected in many of today’s settings,
from a simple at-home blood pressure monitor to a company’s network of devices
and entire public utility grids. With Wi-Fi, homeowners can safely and securely
control smart ovens, electric vehicle charging stations or sprinkler systems to
save time and energy. Building managers can implement remote lighting and
climate systems to conserve resources, enhance comfort and reduce expenses. Grid
operators can wirelessly detect and resolve problems related to maintenance,
energy distribution and security.
Traditionally, Wi-Fi meets performance needs at a manageable cost; it is
ubiquitous, interoperable and familiar. For example, Wi-Fi infrastructure is
common in many spaces, so product designers don’t have to worry about creating
bridges and dongles to connect their products to the internet. Another benefit
of Wi-Fi is the broad ecosystem of technology providers that work in the
Institute for Electrical and Electronics Engineers (IEEE) 802.11 standards arena
– and subsequently with the Wi-Fi Alliance for interoperability testing – to
provide an expanding array of features. However, for the increasingly complex,
diverse connected network that is the Internet of Things (IoT), not everyone
knows the latest Wi-Fi standards, or why they matter.
In the story of Wi-Fi’s evolution, the latest Wi-Fi standard is IEEE 802.11ax,
also known as Wi-Fi 6, and it has several little-known capabilities that are
optimized for cost-sensitive IoT applications. While Wi-Fi is known for
supporting gigabits-per-second, high-throughput options for smartphones and
laptops, Wi-Fi 6 now includes features that scale down to tens of megabits per
second, resulting in new:
* power-saving protocols,
* range enhancements, and
* spectrum additions
— all of which enable the creation of chip- and module-level products that you
can use to easily and affordably add Wi-Fi connectivity to your embedded system
designs.
TI’s CC3301 SimpleLinktm companion IC helps implement Wi-Fi 6 in a configuration
supporting 20-MHz-wide radio-frequency channels along with integrated Bluetooth
Low Energy (BLE). This is an affordable device that you can easily add to a
system design with a single antenna, and it supports approximately 86-Mbps
physical layer throughput. This is more than sufficient for bulk data-oriented
devices such as Internet Protocol (IP) security cameras and printers. It easily
scales for sensors and other instruments that may only need a few
kilobits-per-second throughput, while supporting the flexibility to reflash
quickly (an action that could involve megabytes of data exchange even on a small
sensor).
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Figure 1: Features of Wi-Fi6 that the TI CC301 SimpleLink companion IC
supports (source: Wi-Fi Alliance).
TI supports CC3301 and others in the SimpleLink Wi-Fi 6 family with software
offerings that also scale well for IoT computing resources, ranging from
microprocessor (MPU)-based products that run embedded Linux® to microcontroller
(MCU)-based products that run FreeRTOS. The family includes offerings with a
2.4-GHz radio, as well as dual-band 2.4- and 5-GHz and tri-band 2.4-, 5- and
6-GHz products. Additionally, some products include BLE, which you can use for
Wi-Fi provisioning or as an embedded gateway.
While Wi-Fi 6 is known for its high-throughput capabilities, there are several
features that also bring benefits to IoT applications in the areas of new
spectrum, advanced security, power reduction and latency management. The table
below (Figure 2) summarizes of some of these features:
Wi-Fi 6 feature
Benefit for IoT applications
Wi-Fi protected access 3 security
This provides the latest security protocols for consumer and enterprise
networks. It is available as an option for earlier generations of Wi-Fi, but is
a prerequisite for Wi-Fi 6.
Access to the newly allocated 6-GHz spectrum
Up to 1 GHz of new unlicensed spectrum is being made available worldwide in the
6-GHz band for use by Wi-Fi 6. This will reduce network congestion and in turn
improve throughput, while reducing latency and power consumption. (Earlier
generations of Wi-Fi will not operate in the 6-GHz band.)
Target wake-time protocol
Enables flexibility for a product to negotiate wake and sleep timing with a
Wi-Fi access point, which may help extend battery life in power-sensitive
applications.
Trigger frames sent from an access point
Wi-Fi 6 allows the access point to send trigger frames to specific products on
the network that trigger communication. This is an enhancement to the random
transmission and collision technique used on legacy networks. Trigger frames
reduce collisions on the network and improve quality of service.
Orthogonal frequency-division multiple access
This is a physical layer scheme that allows the splitting of a single 20-MHz
channel between as many as nine IoT devices so that they can all transmit and
receive at the same time, allowing for reduced network latency, fewer collisions
and better spectral efficiency.
Multiuser multiple input, multiple output
A technique that allows a single access point to communicate with multiple IoT
products at the same time, thus increasing network capacity and reducing
latency.
Basic service set coloring
A technique that allows an IoT product to transmit if it can detect a signal
from an access point to which it is not connected (earlier Wi-Fi generations do
not allow this). This increases throughput and reduces latency, especially in
dense network deployments.
Figure 2: Potential use cases of Wi-Fi 6 addressed by feature.
With the SimpleLink Wi-Fi 6 family of devices, TI brings the benefits of Wi-Fi 6
to IoT applications that you can evaluate today using TI processor software
development kits and TI MCU LaunchPadtm development kits.
Additional Resources:
• See the data sheet for CC330X devices
• Get started with the EVM
• Learn about all TI Wi-Fi products
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DECREASE FACTORY DOWNTIME IN 24-VDC POWER DISTRIBUTION WITH ADVANCED LOAD
DIAGNOSTICS
April 19, 2023, 7:32 am
Next How can you optimize SWaP for next-generation satellites with electronic
power systems?
Previous How little-known capabilities of Wi-Fi®︎ 6 help connect IoT devices
with confidence
0
0
Other Parts Discussed in Post: TPS274C65
In Industry 4.0, the amount of diagnostic data is growing each year, enabling
systems to become smarter, remain online longer and – in the end – increase
productivity. In programmable logic controller (PLC) systems, robotics and
machine tools, one area that is still traditionally lacking diagnostic data is
24-VDC power, which distributes power to different control systems in a factory.
If something goes wrong with 24-VDC power distribution, the lack of load
diagnostic data often requires long debugging checklists full of rudimentary
steps (such as “Is the power-good LED green or red?”) or intrusive
investigations such as module disassembly, which increases downtime and
decreases productivity.
Current sensing is a load diagnostic that when added to a 24-VDC power
distribution network improves data collection, making it possible to diagnose
overload currents, wire breaks and aging mechanical systems, or identify whether
a load turned on correctly or not all.
The ability to sense current with an analog-to-digital converter (ADC) and a
current-sense amplifier or high-side switch with integrated current monitoring
has always been available. However, given factors such as isolation barriers,
the limited number of ADC channels, or the routing of ADC channels, the
implementation of current sensing can be expensive or difficult.
One way to add current sensing while not overcomplicating a system would be to
use a high-side switch with an integrated ADC. The TPS274C65 packs four 65-mΩ
high-side switches into a 6-mm-by-6-mm quad flat no-lead package which leads to
a reduction in power dissipation of 38% versus similar industrial high-side
switches available in the market. The high-side switch channels and ADC are
controllable and configurable through Serial Protocol Interface communication.
Integrating the current-sense circuitry and ADC in the TPS274C65 enables it to
transfer current-sense data over isolation barriers in digital output modules
and reduce the routing of ADC channels, since all of the routing occurs inside
the chip. Additionally, the device can also sense the temperature of the
internal metal-oxide semiconductor field-effect transistors (MOSFETs) and sense
voltage on the input and outputs.
Figure 1 is a block diagram illustrating how the TPS274C65 in a digital output
module helps increase the amount of data sent back to the PLC controller over
the isolation barrier.
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Figure 1: The TPS274C65 in a digital output module application
Let’s focus now on the TPS274C65’s use in factory applications such digital
outputs; remote input/output (I/O) modules; and larger systems such as robots,
computer numerical control machines and multicarrier systems.
Using current sensing to shorten debugging checklists
As I mentioned above, without diagnostic data, repairing systems can lead to
long debugging checklists or intrusive investigations such as module
disassembly. This can be problematic for complex systems such as robots and
machine tools. The integrated ADC in the TPS274C65 enables both on-site and
remote checks to determine the correct distribution of power to the different
sensors, relays and subsystems, which helps eliminate potential root causes and
enables users to identify problems more quickly. Such monitoring also lets users
know if a subsystem is not working properly – for example, they could bring a
spare part if on-site debugging is required.
Figure 2 shows what a command center for a power-distribution network could look
like in a digital output, remote I/O, machine or robot application. This level
of detail could help provide more information to help find the root cause of an
offline system.
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Figure 2: The TPS274C65USB evaluation module GUI
Using current sensing to provide predictive maintenance and predictive
resolution
To take it one step further, having diagnostic data that shows how a system had
been operating before it failed enables the establishment of a predictive
resolution procedure to prevent future machines from failing in the same way.
For instance, using current sensing to determine whether a small motor or
actuator is drawing more current to perform the same function could mean that it
is aging, close to failure, or that some mechanism might need servicing.
The integrated ADC in the TPS274C65 enables the collection of this data to
perform predictive maintenance and predictive resolution, thus making sure that
downtime is planned rather than unplanned. For example, capturing the
load-current profile of a solenoid valve could detect whether the valve
performance is changing over time. Does the valve have any additional life, or
does it need replacing?
Figure 3 shows how the integrated ADC senses the load-current profile of the
solenoid valve.
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(a)
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(b)
Figure 3: Example of the current-sensing capability of the TPS274C65: a scope
shot showing the load-current profile of a solenoid valve (a); a readout from
the TPS274C65 ADC of the load-current profile of a solenoid valve (b)
Conclusion
The TPS274C65’s current-sensing capabilities in factory automation systems
decrease downtime and increase productivity. In the end, it will really come
down to how you can use this tool in your toolbox to make power distribution
smarter.
Additional resources
* To start evaluating the performance of the TPS274C65, check out the TPS274C65
evaluation module for quad-channel 65-mΩ ON-resistance high-side switch.
* To learn more about TI’s growing portfolio of high-side switches, see the
high-side switches portal page.
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HOW CAN YOU OPTIMIZE SWAP FOR NEXT-GENERATION SATELLITES WITH ELECTRONIC POWER
SYSTEMS?
April 19, 2023, 6:24 am
Next Processing the advantages of zone architecture in automotive
Previous Decrease factory downtime in 24-VDC power distribution with advanced
load diagnostics
0
0
Other Parts Discussed in Post: TPS7H5001-SP, TPS7H5005-SEP
In the satellite industry, dramatic increases in local data processing, support
for higher throughput communication links and the rapid adoption of electrical
propulsion systems are driving demand for much higher performance electrical
power systems (EPSs). The EPS is part of the bus section of a satellite,
providing structural support and housing subsystems such as power, thermal
management, communication and propulsion. The EPS generates, stores, regulates
and distributes power to all other subsystems and payloads onboard the
satellite.
The unique challenges and constraints of space missions require optimizing size,
weight and power (SWaP). Here are some of the reasons why SWaP is such a big
deal in satellite designs:
* Mission requirements: Requirements such as data transmission rate, resolution
and sensitivity can impact a satellite’s SWaP requirements.
* Launch limitations: Satellites have size constraints, weight constraints and
cost-of-launch constraints that can be $10,00 to $1000,00 per kilogram based
on the intended orbit.
* Power generation: Satellites generally rely on solar panels, and the size and
weight of the panels limit the amount of generated power. The
power-generation capacity also affects the weight and size of components,
like batteries, and functions such as power distribution and thermal
management.
* Operational efficiency: SWaP optimization enables satellites to operate more
efficiently in space, resulting in better performance and longer mission
lifetimes.
Because power is one of the most valuable resources on a satellite, maximizing
EPS efficiency can help extend mission lifetimes, reduce mass and volume, and
minimize thermal management overhead.
Beyond efficiency, an EPS must also handle a wide range of voltages and currents
because of the number of power-supply topologies. Figure 1 shows some of the
most common topologies.
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Figure 1: Common power-supply topologies in satellite power architectures
The components and functions, shown in Figure 2, of a typical satellite EPS are:
* Solar panels (or energy generation): Solar panels are the primary power
source for most satellites.
* A battery (or energy storage): The battery stores excess power generated by
the solar panels during daylight hours, and provides power to the satellite
during an eclipse or when the solar panels are not generating enough power.
* Power-conditioning unit (PCU): The PCU regulates the electrical output of the
solar panels and battery to provide a stable and consistent voltage and
current to the rest of the satellite.
* Power-distribution unit (PDU): The PDU distributes power generated by the
solar panels and battery to the various subsystems and payloads onboard the
satellite.
* Backup power supply: If the primary EPS fails, a backup power supply will
help maintain the most essential functions until the restoration of the
primary system.
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Figure 2: A typical satellite EPS
One way to optimize the SWaP design challenge in these types of systems is to
use pulse-width modulation (PWM) controllers. For example, the
radiation-hardened TPS7H5001-SP (100 krad TID, 75 MeV⋅cm2/mg) and
radiation-tolerant TPS7H5005-SEP (rad-tolerant 30 to 50 krad TID, 43 MeV⋅cm2/mg)
controller families enable the use of a common power architecture for many of
the circuits in an EPS across a number of different missions and diverse orbits.
To help engineers optimize the SWaP in their satellite power system, the
following reference designs use space-grade space-grade PWM controllers in
various power-supply circuits across the satellite, not only in the EPS, but
also on select payload boards:
* Isolated flyback design:
* A 100-W isolated synchronous flyback topology that supports an input of 22
V to 36 V with an output of 5 V and uses GaN FETs in the power stage.
* This design is optimized for power-supply topologies that require only a
single output.
* Non-isolated high-current dual-phase buck design:
* This design uses the TPS7H5001-SP controller in a single-phase synchronous
buck topology supporting an input of 11 V to 14 V with an output of 1 V and
uses GaN FETs in the power stage. The design is capable of supporting 20 A
and maintains tight DC and AC tolerance.
* You can extend this design to a multiphase solution optimized for payload
designs that require high current (>50 A) and low input voltages (sub-1 V)
to power the core rails of some advanced field-programmable gate arrays and
multicore central processing units.
Conclusion
With power being one of the most valuable resources on a satellite, the EPS
architecture can have a significant impact on the overall design. TI’s
radiation-validated PWM controller families provide high efficiency and support
a wide range of topologies, as well as an architecture that’s deployable in a
diverse set of missions and orbits.
Additional resources
* Check out the TI Space Products Guide, Radiation Handbook for Electronics and
Spacecraft Circuit Design Handbook.
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PROCESSING THE ADVANTAGES OF ZONE ARCHITECTURE IN AUTOMOTIVE
April 21, 2023, 1:39 am
Next How to maximize SiC traction inverter efficiency with real-time variable
gate drive strength
Previous How can you optimize SWaP for next-generation satellites with
electronic power systems?
0
0
Think of a passenger car as a collection of electronic control units (ECUs) that
are distributed across the length and breadth of the car and talk to each other
using different networks. When adding more advanced automotive electronics for
vehicle-to-everything (V2X), automated driving and vehicle electrification, the
number of ECUs increases and the amount of data exchanged grows.
Moreover, the increased number of ECUs has diversified network types, from Local
Interconnect Network (LIN) and Controller Area Network (CAN) to higher-speed
networks such as Flat Panel Display-Link (FPD-Link), PCI Express (PCIe) and
Ethernet.
In a domain architecture, ECUs are categorized into domains based on their
function, but the zone architecture is a new approach that classifies ECUs by
their physical location inside the vehicle, leveraging a central gateway to
manage communication. This physical proximity reduces cabling between ECUs to
save space and reduce vehicle weight, while also improving processor speeds.
The domain architecture explained simply
To understand the domain architecture, it helps to start by understanding the
five domains in which ECUs are typically categorized based on function, as shown
in Table 1.
SKIP THE INTRODUCTION ON DOMAIN ARCHITECTURE, AND GO STRAIGHT TO ZONE
ARCHITECTURE.
Domain
ECU function
Powertrain domain
Manages the function of driving of a car, including electric motor control and
battery management, engine control, transmission and steering control
Advanced driver assistance system domain
Processes sensor information and takes decisions to assist the driver, including
the camera module, radar module, ultrasonic module and sensor fusion
Infotainment domain
Manages entertainment within the vehicle and exchanges information between the
vehicle and the outside world, including the head unit, digital cockpit and
telematics control module
Body electronic and lighting domain
Manages comfort, convenience and lighting functions in the car, including the
body control module, door module and headlight control module
Passive safety domain
Controls safety-related functions such as the airbag control module, braking
control module and chassis control module
Table 1: ECUs are typically classified into five domains
The ECUs communicate and exchange data over networks that are specific and
relevant inside their own domain while also communicating with ECUs in outside
domains. Since the network in one domain could differ from the network in
another domain, a gateway serves as a bridge.
Figure 1 illustrates a vehicle with a domain-based network architecture. In this
figure, there is a central gateway module connected to the different domains in
the car. Each domain performs several functions. The domain controller (such as
the powertrain, for example) includes gateway function. This domain gateway
helps communicate data across the ECUs supporting the relevant domain and from
the domain to rest of the vehicle.
The domain controller also incorporates ECUs, which helps minimize system cost
by integrating the functionality typically implemented through multiple ECUs.
TI’s JacintoTM 7 processors integrate Arm® Cortex® A-72 cores for raw processing
power to handle the data, an Arm Cortex R-5Fs for real-time control and gigabit
time-sensitive network (TSN) and Ethernet switch for high-speed networking.
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Figure 1: Domain architecture
Introducing the zone architecture
If the car was a room and the ECUs were people gathered in that room to discuss
different topics, a domain architecture is equivalent to chaotically arranging
those people, causing them to shout to others in their discussion groups across
the room.
A zone architecture organizes the ECUs based on their location inside the car
and adds a vehicle compute module. The vehicle compute module is a computer with
a large processing capacity to perform all computations regardless of function.
This architecture could also include a gateway module to manage network
traffic.
Figure 2 depicts the zone modules and associated zone satellite modules in
different regions of the car, along with the central gateway and vehicle compute
modules. TI’s Jacinto DRA82x processors for automotive are tailor-made for
gateway systems and include features to move data in the vehicle safely and
securely. The DRA82x processor family includes devices with an integrated PCIe
switch and Gigabit TSN Ethernet switch, which can be used in compute platforms,
central gateways and zone modules.
It is possible to use a low-bandwidth network such as CAN for communication
between the different zone modules and the central gateway/compute modules.
However, high-speed networks such as Ethernet or PCIe are also a good choice
because they provide high reliability and smooth operation in a range of
automotive temperatures.
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Figure 2: Zone architecture
Power advantages of a zone architecture
Engineers are also taking advantage of this reorganization of ECUs to optimize
power architectures – specifically the redesign of smart junction boxes, also
called power distribution modules, which distribute power to different loads and
ECUs in the vehicle. The power distribution boxes are somewhat specific to the
car model, and each power distribution box distributes power to a specific set
of loads.
Since most power distribution box designs use relays and fuses, they must be
easily accessible if a fuse needs to be replaced. In a zone architecture, the
power distribution boxes are distributed so that each zone has its own power
distribution unit to power the modules in the corresponding zone.
Figure 3 shows the concept of power distribution in a zone architecture, where
you can see the integration of each zone’s power distribution module function
with the zone module that manages the network traffic and local zone
satellites. Image may be NSFW.
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Figure 3: Power distribution modules in a zone architecture
Another advantage is that power distribution module designs can be similar
throughout the vehicle. Using semiconductor solutions such as smart high-side
switches instead of mechanical relays and fuses enables a more sensible power
distribution module design, locating modules closer to the loads instead of
farther away so that they are more accessible for replacement.
Tailor-made gateway processors lay the groundwork for zone architectures
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Read the article
Conclusion
With the increase in the number of ECUs, the vehicle network has evolved into a
domain architecture where the ECUs are grouped based on a related function that
each ECU is performing. This has increased network complexity, however.
Automotive vehicle designers are now considering the use of a zone-based
architecture, which offers the advantage of having a vehicle compute module to
control vehicle functions.
Taking advantage of this new network architecture enables you to optimize the
vehicle power architecture, specifically considering installation of the local
power distribution module in each zone along with the zone module that manages
network traffic and zone satellite modules. The new zone architecture will
ultimately lead to a harness cable weight reduction, which results in higher
fuel efficiency for internal combustion engine-based vehicles and higher driving
ranges for battery-powered electric vehicles.
For more information, please read the whitepaper: How a Zone Architecture Paves
the Way to a Fully Software-Defined Vehicle.
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HOW TO MAXIMIZE SIC TRACTION INVERTER EFFICIENCY WITH REAL-TIME VARIABLE GATE
DRIVE STRENGTH
May 8, 2023, 9:50 am
Next How silicon carbide helps maximize efficiency in renewable energy systems
Previous Processing the advantages of zone architecture in automotive
0
0
Other Parts Discussed in Post: UCC5880-Q1
Traction inverters are the main consumer of battery power in electric vehicles
(EVs), with power levels reaching 150 kW or higher. The efficiency and
performance of traction inverters directly impact an EV’s driving range on a
single charge. Therefore, to build the next generation of these systems, the
industry has widely adopted silicon carbide (SiC) field-effect transistors
(FETs) to enable higher reliability, efficiency and power density.
The isolated gate-driver integrated circuits (ICs) provide low- to high-voltage
(input-to-output) galvanic isolation, drive the high- and low-side power stages
of each phase of a SiC-based inverter, and monitor and protect the inverter
against various fault conditions. Depending on the Automotive Safety Integrity
Level (ASIL) functional safety requirements, the gate-driver IC may have to be
International Organization for Standardization (ISO) 26262-compliant, ensuring
fault detection of ≥99% and ≥90% for single and latent faults, respectively.
In this article, I’ll focus on the benefits of real-time variable gate-drive
strength, a new feature that enables designers to optimize system parameters
such as efficiency (which impacts EV operating range) and SiC overshoot (which
impacts reliability).
Higher efficiency with real-time variable gate-drive strength
The gate-driver IC has to turn on the SiC FETs as efficiently as possible, while
minimizing switching and conduction losses that include both turnon and turnoff
energy. The ability to control and vary the gate-drive current strength reduces
switching losses, but at the expense of increasing transient overshoot at the
switch node during switching. Varying the gate-drive current controls the slew
rate of the SiC FET.
Real-time variability of the gate-drive current enables transient overshoot
management as well as design optimization throughout the high-voltage battery
energy cycle. A fully charged battery with a state of charge from 100% to 80%
should use low gate-drive strength to maintain SiC voltage overshoot within the
limits. As the battery charge drops from 80% to 20%, employing high gate-drive
strength reduces switching losses and increases traction inverter efficiency.
These scenarios are possible during 75% of the charging cycle, so the efficiency
gains can be quite significant.
The UCC5880-Q1 is a 20-A SiC gate driver that has advanced protection features
for traction inverters in automotive applications. Its gate-drive strength
varies from 5 A to 20 A, and is variable through both a 4-MHz bidirectional
Serial Peripheral Interface bus or three digital input pins.
Evaluating power-stage switching with DPT
A standard way to evaluate a traction inverter’s power-stage switching
performance is the double pulse test (DPT), which turns the SiC power switch on
and off at different currents. Varying the switching times makes it possible to
control and measure the SiC turnon and turnoff waveforms over operating
conditions, thus facilitating an evaluation of efficiency and SiC overshoot,
which affects reliability.
Extending driving range
When using the UCC5880-Q1’s strong gate drive to reduce SiC switching losses,
the efficiency gain can be quite significant, depending on the traction
inverter’s power level. Modeling with the Worldwide Harmonized Light Vehicles
Test Procedure (WLPT) and real drive log speed and acceleration settings has
shown SiC power-stage efficiency gains as high as 2%, corresponding to an
additional 7 miles of range per battery. Seven miles could mean the difference
between a consumer reaching a charger versus getting stranded.
The UCC5880-Q1 also includes a SiC gate-voltage threshold monitoring feature
that performs threshold voltage measurements at every EV key-on over a system’s
lifetime, and can provide power-switch data to the microcontroller for
power-switch failure prediction.
Conclusion
With EV traction inverters approaching 300-kW power levels, the need for higher
reliability and higher efficiency is imperative. Selecting a SiC isolated gate
driver with real-time variable gate-drive strength is useful in achieving these
goals. The UCC5880-Q1 comes with design support tools including evaluation
boards, user’s guides and a functional safety manual to assist you with your
designs.
Additional resources
* Read the white paper, “Traction Inverters – A Driving Force Behind Vehicle
Electrification.”
* See the TI E2E technical article, “Improving Safety in EV Traction Inverter
Systems.”
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HOW SILICON CARBIDE HELPS MAXIMIZE EFFICIENCY IN RENEWABLE ENERGY SYSTEMS
May 12, 2023, 9:19 am
Next Selecting the right level of integration to meet motor design requirements
Previous How to maximize SiC traction inverter efficiency with real-time
variable gate drive strength
0
0
Other Parts Discussed in Post: UCC21710 There is an energy revolution happening
across the world, where according to the International Energy Agency, renewable
energy sources will account for almost 95% of the increase in global power
capacity throug...(read more)Image may be NSFW.
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SELECTING THE RIGHT LEVEL OF INTEGRATION TO MEET MOTOR DESIGN REQUIREMENTS
May 10, 2023, 12:17 pm
Next How to deliver current beyond 100 A to an ADAS processor
Previous How silicon carbide helps maximize efficiency in renewable energy
systems
0
0
Other Parts Discussed in Post: UCC21732, UCC27712, DRV8329, DRV8962, MCT8329A,
MCF8315AThis article is part three of our motion control technical article
series (part one | part two) If you’re designing a motor-drive application,
you’ve l...(read more)Image may be NSFW.
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HOW TO DELIVER CURRENT BEYOND 100 A TO AN ADAS PROCESSOR
June 6, 2023, 6:55 am
Next How to enhance power and signal integrity with low noise and low ripple
design techniques
Previous Selecting the right level of integration to meet motor design
requirements
0
0
Other Parts Discussed in Post: TPS62876-Q1
The electrification of vehicle systems is growing in advanced driver assistance
systems (ADAS), which include vision analytics for autonomous driving, parking
assistance and adaptive control functions. Smart connectivity, safety-critical
software applications, and neural network processing all require enhanced
computing power in real time.
Meeting these advanced needs requires a multicore processor such as the
TDA4VH-Q1, which can support electronic control units (ECUs) beyond 100 A. But
the design challenges associated with high power include achieving efficiency
for higher current rails, controlling thermal performance and load transients at
full loads, and meeting functional safety requirements.
Delivering ADAS processing power
Stacking these devices not only helps power the core of next-generation ADAS
SoCs, but also helps improve thermal performance by reducing thermal
limitations, and increase efficiency. See Figure 1.
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Figure 1: Two TPS62876-Q1 devices in a stacked configuration
Stacking operates by using the daisy-chain method. The primary device controls
one compensation network, one POWERGOOD pin, one ENABLE pin and one I2C
interface. For optimal current sharing, you must program all devices in the
stack to use same current rating, the same switching frequency and the same
current level.
The primary device in the stack also sets the output voltage and controls its
regulation. If there is a 47-kΩ resistor between the SYNCOUT pin and ground, the
device operates as a secondary device. If the SYNCOUT pin is high impedance, the
device operates as a primary device. Figure 2 shows the stack configuration
implemented on a printed circuit board.
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Figure 2: Example evaluation module of three stacked TPS62876-Q1 buck converters
Other features in this family of buck converters include:
* Droop compensation, also known as load line (automatic voltage positioning).
Scaling the nominal output voltage provides better load-transient tolerance
based on the output current (15 A to 30 A) and helps reduce the output
capacitance, enabling a cost-optimized, high-power-density solution. The
REGISTER pin enables or disables droop compensation, which is disabled by
default.
* Remote sensing supports a wider range of SoC processors with a tighter
output-voltage requirement that provides more headroom during load
transients. The device’s remote sense lines connect directly to the point of
load, which allows you to set the voltage with an accuracy of 0.8%.
* The I2C interface monitors system performance and sends a warning if the
temperature and output current exceed specified limits. It is also possible
to use dynamic voltage scaling to adjust the output voltage from 0.4 V to
1.675 V. If you do not need the I2C feature, you can still use same device by
connecting the SCL and SDA pins to ground.
Functional safety
Functional safety is an important aspect in ADAS, especially when it comes to
autonomous driving. The TPS62876-Q1 buck converter offers TI Functional
Safety-Capable levels of documentation, which include:
* The functional safety failure-in-time rates of the semiconductor component
estimated by the application of industry reliability standards.
* Component failure modes and their distribution based on the device’s primary
function.
* Pin failure-mode analysis.
Adding an external supervisor to your design enables you to achieve Automotive
Safety Integrity Level standards.
Conclusion
Moving toward higher autonomy levels such as Society of Automotive Engineers
Level 2 will require more computational capabilities to provide higher
resolutions and quick responses in a very short time. Embedding features such as
artificial intelligence technologies also increases the need for more
power-hungry ADAS SoC processors. The stackability of the TPS62876-Q1 family
helps you achieve core power beyond 100 A to enable a higher level of autonomous
driving.
Additional resources
* Read the technical article, “Minimize the Impact of the MLCC Shortage on Your
Power Application.”
* Download the TPS6287x-Q1 data sheet.
* Check out the “TPS62876 Buck Converter Evaluation Module” user’s guide.
* See the TPS62874-Q1, TPS62875-Q1, TPS62876-Q1 and TPS62877-Q1 Functional
Safety FIT Rate, FMD and Pin FMA functional safety information.
* Find the right Arm®-based processor for your automotive needs.
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HOW TO ENHANCE POWER AND SIGNAL INTEGRITY WITH LOW NOISE AND LOW RIPPLE DESIGN
TECHNIQUES
June 7, 2023, 7:30 am
Next Powering smart sensor transmitters in industrial applications
Previous How to deliver current beyond 100 A to an ADAS processor
0
0
Other Parts Discussed in Post: TPSM82912, TPS7A94, TPSM82913, TPS62913, TPS62912
Improving accuracy and precision, and minimizing system noise is a common
challenge for engineers designing a power supply for noise-sensitive systems for
medical applications, test and measurement, and wireless infrastructure that use
clocks, data converters or amplifiers. Although the term “noise” can mean
different things to different people, in this article I’ll define noise as
low-frequency thermal noise generated by resistors and transistors in the
circuit. You can identify noise through a spectral noise-density curve in
microvolts per square-root hertz, and as integrated output noise in
root-mean-square microvolts, typically over a specific range from 10 Hz to 100
kHz. Noise in the power supply can degrade the analog-to-digital converter’s
performance and introduce clock jitter.
The traditional setup for powering a clock, data converter or amplifier is to
use a DC/DC converter (or module), followed by a low-dropout regulator (LDO)
such as the TPS7A94, TPS7A82, TPS7A84, TPS7A52, TPS7A53 or TPS7A54, followed by
a ferrite-bead filter, as shown in Figure 1. This design approach minimizes both
noise and ripple from the power supply and works well for load currents below
approximately 2 A. As loads increase, however, the power loss in the LDO
introduces issues in efficiency and thermal management; for example, a
post-regulation LDO can add 1.5 W of power loss in a typical analog front-end
application. Are those of you looking for low noise and efficiency in your
design out of options? Not quite.
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Figure 1: A typical low-noise architecture using a DC/DC converter, LDO and
ferrite-bead filter
Using a low-noise buck converter or module in place of an LDO
One way to keep the power loss in check is to minimize the dropout through the
LDO. However, this approach will have a negative impact on noise performance.
Additionally, higher-current LDOs are typically larger, which can increase
design footprints and cost. A more effective way to ensure low noise while
controlling the power loss is to eliminate the LDO from the design altogether
and use a low-noise DC/DC buck converter or module, as shown in Figure 2.
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Figure 2: Using a low-noise buck converter without an LDO
I know what you’re thinking: How does removing the primary device that reduces
noise still provide a low-noise supply? Many LDOs have a low-pass filter on the
bandgap reference to minimize the noise into the error amplifier. The TPS62912
and TPS62913 family of low-noise buck converters, as well as the TPSM82912 and
TPSM82913 modules, implement a noise-reduction/soft-start pin for connecting a
capacitor, forming a low-pass resistor-capacitor filter using the integrated
Rf and externally connected CNR/SS, as shown in Figure 3. This implementation
essentially mimics the behavior of the bandgap low-pass filter in an LDO. If you
still need lower noise than the TPS62913 or TPSM82913 can provide, you can use a
low noise LDO like the TPS7A94 with a reduced dropout, lower power dissipation,
and still achieve extremely low noise. This is explained in more detail in App
Brief SBVA099.
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Figure 3: Low-noise buck block diagram with bandgap noise filtering
What about the output voltage ripple?
Every DC/DC converter generates an output voltage ripple at its switching
frequency. Noise-sensitive analog rails in precision systems need the lowest
supply voltage ripple to minimize frequency spurs in the spectrum, which
typically depend on the switching frequency of the DC/DC converter, inductor
value, output capacitance, equivalent series resistance and equivalent series
inductance. To mitigate the ripple from these components, engineers often use an
LDO and/or a small ferrite bead and capacitors to create a pi filter to minimize
ripple at the load. A low-ripple buck converter such as the TPS62912 and
TPS62913, as well as the TPSM82913 module, leverage this ferrite-bead filter by
integrating ferrite-bead compensation and remote-sense feedback. Using the
inductance of the ferrite bead in combination with an additional output
capacitor removes the high-frequency components in the output voltage ripple and
reduces the ripple by approximately 30 dB, as shown in Figure 4.
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Figure 4: Output voltage ripple before the ferrite-bead filter (a); and after
the ferrite-bead filter (b)
Conclusion
By integrating features that mitigate system noise and ripple, low-noise buck
converters can help engineers achieve a low-noise power-supply solution without
the need for an LDO. Of course, the noise levels required by different
applications will vary, as will the performance for different output voltages,
so only you can determine the best low-noise architecture for your design. But
if you’re looking to simplify the design of noise-sensitive analog power
supplies, reduce power losses, and shrink the overall design footprint, consider
using a low-noise buck converter.
Additional resources
* Read the application notes:
* Minimize System Noise with 12 V-to-3.3 V 1 A Low Noise Power Supply
* "Powering Sensitive ADC Designs with the TPS62913 Low-Ripple and Low-Noise
Buck Converter."
* "Powering the AFE7920 with the TPS62913 Low-Ripple and Low-Noise Buck
Converter."
* For details about the output voltage ripple contribution when using a DC/DC
converter, read the technical article, “Understanding and managing buck
regulator output ripple.”
* To learn more about lowering noise and ripple with the TPS62913 and the
TPS62913, watch the video training:"Low ripple & Low Iq DC/DC point-of-load
buck converters."
*
* To see other ways of reducing output voltage ripple from a buck converter,
read the whitepaper Low-noise and low-ripple techniques for a
high-efficiency, low-loss supply without an LDO
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POWERING SMART SENSOR TRANSMITTERS IN INDUSTRIAL APPLICATIONS
June 30, 2023, 5:00 am
Next How solid-state relays simplify insulation monitoring designs in
high-voltage applications
Previous How to enhance power and signal integrity with low noise and low ripple
design techniques
0
0
Other Parts Discussed in Post: LMR36501, LM5165Smart sensor transmitters are
widely used in factory automation, process instrumentation and control equipment
to measure temperature, pressure, flow, level and many other process variables.
Figure 1 is ...(read more)Image may be NSFW.
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HOW SOLID-STATE RELAYS SIMPLIFY INSULATION MONITORING DESIGNS IN HIGH-VOLTAGE
APPLICATIONS
July 12, 2023, 8:50 am
Previous Powering smart sensor transmitters in industrial applications
0
0
Other Parts Discussed in Post: TPSI2140-Q1, BQ79731-Q1
In electric vehicles, solar panels and energy storage systems, high-voltage
power achieves faster charge times, minimizes power losses, and improves design
reliability. High-voltage currents have the potential to be dangerous or even
deadly, however, so designers use insulation monitoring systems to send an alert
or disconnect the power supply to prevent harm to the application or users.
Quickly and accurately detecting faults in insulation is vital for maximizing
user safety and minimizing damage or fire resulting from a catastrophic loss of
power.
Common applications with insulation monitoring include battery management
systems, energy storage systems, string inverters, DC fast chargers, DC wall-box
chargers, solar panels, motors and planes. But accuracy and withstand voltage
test requirements can make insulation monitoring challenging to design. TI has
both reference designs and devices designed to simplify the design process.
Navigating the design challenges of insulation monitoring
Insulation monitoring, also known as insulation check, isolation monitoring,
isolation check, ground fault detection or ground fault sensing, monitors the
amount of insulation between high-voltage terminals and protective earth/chassis
ground. Figure 1 illustrates one configuration for insulation monitoring. The
basic operation of an insulation monitoring circuit involves switching in known
resistances (RDIV1/2, RDIV3/4) and solving a system of equations in order to
find the unknown insulation resistances (RISOP, RISON).
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Figure 1: Insulation monitoring configuration
Addressing strict safety requirements
Safety standards require that manufacturers evaluate the effectiveness of a
given electrical or electronic device’s insulation for safety by performing a
dielectric voltage withstand test (also called a high-potential test). The
dielectric voltage withstand test applies high voltages across the insulation
barrier for one minute. A measured insulation post-test that meets the
manufacturer’s requirement threshold is considered a passing grade.
According to International Electrotechnical Commission (IEC) 60950, the
withstand voltage test for basic insulation is 2U + 1,000 VRMS, where U is the
maximum operating voltage of a system. A manufacturer may need to apply a
4,242-V withstand voltage test when designing an 800-V system based on Equation
1:
2 x 1,000 V (added battery charge margin) +1,000=3,000 VRMS=4,242 VDC
(1)
Figure 2 illustrates this withstand voltage test, taking the previous insulation
monitoring configuration, removing the high-voltage battery, and applying 4,242
V across a terminal and chassis ground.
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Figure 2: Insulation monitoring high-potential example
Since the switches (SW1, SW2) are often solid-state relays or photo relays with
integrated metal-oxide semiconductor field-effect transistors, you must make
component considerations to ensure switch survivability. These switches are
typically rated for a limited amount of avalanche current (Iava) over a span of
time, so for example, during component selection you may need to choose series
resistors that can adequately limit the avalanche current, or add an expensive
reed relay to ground in order to prevent avalanche current flow altogether.
Unfortunately, having a large series resistance can negatively impact
measurement accuracy, so selecting resistors with resistances similar in value
to the insulation resistance will maximize accuracy.
The advantages of solid-state relays
You can use photo relays, but there are drawbacks in comparison to solid-state
relays in terms of avalanche current, speed, reliability and solution size. The
TPSI2140-Q1 supports up to 2 mA of avalanche current, compared to 0.6 mA in a
generic photo relay. A generic photo relay is also typically limited in
switching speed by its LED and forward bias requirements. Photo relays suffer
from photo degradation over time and in size, requiring additional components to
create drive circuitry.
Figure 3 shows the TPSI2140-Q1 functional block diagram.
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Figure 3: TPSI2140-Q1 functional block diagram
Depending on additional system requirements, you may wish to consider a
configuration using an intelligent battery junction box such as the BQ79731-Q1
battery pack monitor to measure voltage, temperature and current.
The AFE for Insulation Monitoring in High-Voltage EV Charging and Solar Energy
Reference Design and Automotive High-Voltage and Isolation Leakage Measurements
Reference Design both use the TPSI2140-Q1 solid-state relay for switching in
known resistances.
Designers sometimes opt into purchasing insulation monitoring modules in order
to avoid the challenges of factoring in withstand voltage test design
considerations. Both reference designs use different topologies to address
insulation monitoring, featuring good accuracy for fault detection, support for
safety standards, scalability and more.
The AFE reference design is capable of accurately and reliably monitoring the
insulation resistance, maintains insulation during insulation resistance
measurements, and supports IEC 61557-8 and IEC 61851-23.
Figure 4 depicts the AFE reference design block diagram.
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Figure 4: AFE reference design block diagram
Figure 5 depicts the block diagram for the leakage measurements reference
design.
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Figure 5: Leakage measurements reference design block diagram
Conclusion
The shift to higher voltages to minimize charging times – such as EVs trending
from 400 V to 800 V and solar energy shifting toward higher voltage systems –
increases the need for reliable safety and insulation monitoring methods.
Insulation monitoring detects insulation resistance by monitoring the leakage
current from high-voltage terminals to protective earth/chassis ground. Since
currents above 10 mA can be fatal, insulation monitoring systems must provide
warnings upon the detection of faults in the insulation.
TI’s solid-state relays provide the highest operating temperature and highest
dielectric strength at the highest speeds while being cost-effective. They also
provide reliable switching contained in a small package. Discover more about how
to optimize your design using our isolated switches and drivers in the
additional resources below.
Additional resources
* Watch “Introduction to Isolation” in our TI Precision Labs training series.
* Check out our solid-state relay portfolio.
* More information, read the technical article, “How to achieve
higher-reliability isolation and a smaller solution size with solid-state
relays.”
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