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I recently came across a September 18 article by the “future technology” editor at The Wall Street Journal, “Solar-Powered Cars and Trucks Are Almost Here” (sorry, behind paywall, but your local library may have free access). The author was positively gushing about companies such as Aptera Motors (California), which will “soon” be selling all-solar-powered cars. On a full daylight charge, they can do a few tens of miles, then it’s time to park in the Sun for that totally guilt-free “fill up.”

Figure 1 The Aptera solar-powered three-wheel “car” can go between 15 and 40 miles on a full all-solar charge. Source: Aptera Motors

The article focused on the benefits and innovations, such as how Aptera claims to have developed solar panels that withstand road hazards, including rocks kicked up at high speed, and similar advances.

The solar exposure-versus-distance numbers are very modest, to be polite. While people living in a sunny environment could add up to 40 miles (64 km) of range a day in summer months, from panels alone, that drops to around 15 miles (24 km) a day in northern climates in winter. Aptera says its front-wheel-drive version goes from 0 to 60 mph (96 km/hour) in 6 seconds, and has a top speed of 101 mph (163 km/hr).

The article also mentions that Aptera is planning to sell its ruggedized panels to Telo Trucks, a San Carlos (Calif) maker of a 500-horsepower mini-electric truck estimated to ship next year, which uses solar panels to extend its range by 15 to 30 supplemental miles per day.

Then I closed my eyes and thought, “Wait, haven’t I heard this story before?” Sure enough, I looked through my notes and saw that I had commented on Aptera’s efforts and those of others back in a 2021 blog, “Are solar-powered cars the ultimate electric vehicles?”  Perhaps it’s no surprise, but the timeline then was also “coming soon.”

The laws of physics conspire to make this a very tough project. This sort of ambitious project requires advances across multiple disciplines. There are the materials for the vehicle itself, batteries, rugged solar panels, battery-management electronics —  it’s a long list. These are closely tied to key ratios beginning with power and energy to weight.

Did I mention it’s a three-wheel vehicle (with all the stability issues that brings), seats two people, and is technically classified as a motorcycle despite its fully enclosed cabin? Or that it has to meet vehicle safety mandates and regulations? Will drivers likely need power-draining air conditioning unless they drive open-air, especially as the vehicle needs to be parked in the sun by definition?

I don’t intend to disparage the technological work, innovation, and hard work (and money) they have put into the project. Nonetheless, no matter how you look at it, it’s a lot of effort and retail price (estimated to be around $40,000) for a modest 15 to 40 miles of range. That’s a lot of dollar pain for very modest environmental gain, if any.

Is the all-electric vehicle analogous to the flying car?
Given today’s technology and that of the foreseeable future, I think the path of a truly viable all-solar car (at any price) is similar to that other recurrent dream: the flying car. Many social observers say that the hybrid vehicle (different meaning of “hybrid” here, of course) was brought into popular culture in 1962 by the TV show The Jetsons – but there had been articles in magazines such as Popular Science even before that date.

Figure 2 The flying car that is often discussed was likely inspired by the 1962 animated series “The Jetsons.” Source: Thejetsons.fandom.com

Roughly every ten years since then, the dream resurfaces and there’s a wave of articles in the general media about all the new flying cars under development and road/air test, and how actual showroom models are “just around the corner.” However, it seems like we are always approaching but not making the turn around that corner; Terrafugia’s massive publicity wave, followed by subsequent bankruptcy, is just one example.

The problem for flying cars, however attractive the concept may be, is that the priority needs and constraints for a ground vehicle, such as a car, are not aligned with those of an aircraft; in fact, they often contradict each other.

 It’s difficult enough in any vehicle-engineering design to find a suitable balance among tradeoffs and constraints – after all, that’s what engineering is about. For  the flying  car, however, it is not so much about finding the balance point as it is about reconciling dramatically opposing issues. In addition, both classes of vehicles are subject to many regulatory mandates related to safety, and those add significant complexity.

Sometimes, it’s nearly impossible to “square the circle” and come up with a viable and acceptable solution to opposing requirements. Literally, “to square the circle” refers to the geometry challenge of constructing a square with the same area as a given circle but using only a compass and straightedge, a problem posed by the ancient Greeks and which was proven impossible in 1882. Metaphorically, the phrase means to attempt or solve something that seems impossible, such as combining two fundamentally different or incompatible things.

What’s the future for these all-solar “cars”? Unlike talking heads, pundits, and journalists, I’ll admit that I have no idea. They may never happen, they may become an expensive “toy” for some, or they may capture a small but measurable market share. Once prototypes are out on the street getting some serious road mileage, further innovations and updates may make them more attractive and perhaps less costly—again, I don’t know (nor does anyone).

Given the uncertainties associated with solar-powered and flying cars, why do they get so much attention? That’s an easy question to answer: they are fun and fairly easy to write about and the coverage gets attention. After all, they are more exciting to present and likely to attract more attention than silicon-carbide MOSFETs.

What’s your sense of the reality of solar-powered cars? Are they a dream with too many real-world limitations? Will they be a meaningful contribution to environmental issues, or an expensive virtue-signaling project—assuming they make it out of the garage and become highway-rated, street-legal vehicles?

Bill Schweber is an EE who has written three textbooks, hundreds of technical articles, opinion columns, and product features.

Related Content

• Are solar-powered cars the ultimate electric vehicles?
• Keep solar panels clean from dust, fungus
• Home solar-supply topologies illustrate tradeoff realities
• Solar-Driven TEG Advances via Fabrication, Not Materials

References

• Smithsonian Magazine, “Recapping ‘The Jetsons’: Episode 03 – The Space Car”
• Popular Science, “The Flying Car Gets Real”(2008)
• Aircraft Owners and Pilots Association, “AOPA Terrafugia pulls US plug on Transition flying car” (2021)

The post Solar-powered cars: is it “déjà vu” all over again? appeared first on EDN.

The RISC-V Summit North America, held on 22-23 October 2025 in Santa Clara, California, showcased the latest CPU cores featuring new vector processors, high-speed interfaces, and peripheral subsystems. These CPU cores were accompanied by reference boards, software design kits (SDKs), and toolchains.

The show also provided a sneak peek of the RISC-V’s design ecosystem, which is maturing fast with the RVA23 application profile and RISC-V Software Ecosystem (RISE), a Linux Foundation project. The emerging ecosystem encompasses compilers, system libraries, language runtimes, simulators, emulators, system firmware, and more.

“The performance gap between high-end Arm and RISC-V CPU cores is narrowing and a near parity is projected by the end of 2026,” said Richard Wawrzyniak, principal analyst for ASIC, SoC and IP at The SHD Group. He named Andes, MIPS, Nuclei Systems, and SiFive as market leaders in RISC-V IP. Wawrzyniak also mentioned new entrants such as Akeana, Tenstorrent, and Ventana.

Andes, boasting 20 years of expertise in the semiconductor IP business, was a prominent presence in the corridors of the RISC-V Summit in Santa Clara. It’s a founding member of RISC-V International and a pure-play IP vendor. At the RISC-V Summit, Andes displayed its processor lineup, including AX45, AX46, AX66, and Cuzco.

Figure 1 The processor lineup was showcased at the RISC-V Summit in Santa Clara. Source: Andes

Andes claims that these RISC-V processors, featuring powerful compute and efficient control, provide the architectural diversity required in artificial intelligence (AI) applications. AX45 and AX46 processors have been taped out and are shipping in volumes. Here, Andes also provides in-chip firmware, tester software, on-board software, and on-cloud software as part of its hardware IP monitoring offerings.

Though RISC-V is enjoying a robust deployment in automotive, Internet of Things (IoT), and networking, AI was all the rage on the RISC-V Summit floor. “If RISC-V has a tailwind, it’s AI,” Wawrzyniak said.

RISC-V world’s AI moment

Andes claims it’s driving RISC-V into the AI world with features such as advanced vector processing. And that its RISC-V processors are powering devices from the battery-sipping edge to high-performance data centers. Andes also claims that 38% of its revenue comes from AI designs.

Companies like Andes can also bring differentiation and efficiency to AI processor designs through automated custom extensions. “We are getting there, and the deployment speed is impressive,” said Dr. Charlie Su, president and CTO of Andes Technology.

Figure 2 Meta deployed two generations of AI accelerators for training and inference using RISC-V vector/scalar cores. Source: Andes

“RISC-V is getting better for AI applications in data centers,” said Ty Garibay, president of Condor Computing. “RVA23 has a massive investment in features for data center-class AI designs.” Condor Computing, a wholly owned subsidiary of Andes, founded in 2023, develops high-performance RISC-V IPs and is based in Austin, Texas.

Wawrzyniak of SHD Group acknowledges that AI applications are driving the adoption of RISC-V-enabled system-on-chips (SoCs). “The heterogeneous nature of SoCs has created opportunities for multiple CPU architectures,” he said. “These SoCs can support both RISC-V and other ISAs, allowing applications to pick the best core for each function.”

Moreover, the diverse needs for AI acceleration are fueling the demand for RISC-V. “RISC-V CPU IP vendors can more easily introduce new and more powerful CPU cores, which extends the reach of RISC-V into AI applications that require greater compute power,” Wawrzyniak said.

During his keynote, Wawrzyniak said that initial RISC-V deployments were driven by embedded applications such as networking, smart sensors, storage, and wearables. “RISC-V is now transitioning to higher-end applications like ADAS and data centers as AI expands to those applications.”

RISC-V processor duo

At the RISC-V Summit, Andes provided more details about its new application processors. It showcased AX66, a mid-range application processor, and Cuzco, a high-end application processor; both are RVA23-compliant. AX66—incorporating up to 8 cores—features dual vector pipes with VLEN=128 and front-end decode 4-wide. It has a shared L3 cache of up to 32 MB.

Figure 3 AX66 is a 64-bit multicore CPU IP for developing a high-performance quad-decode 13-stage superscalar out-of-order processor. Source: Andes

On the higher end, Cuzco features time-based scheduling with a time resource matrix to determine instruction issue cycles after decoding, thereby reducing logic complexity and dynamic power for wide machines. Cuzco’s decode is either 6-wide or 8-wide, and it has 8 execution pipelines (2 per slice).

Cuzco incorporates up to 8 cores and offers a shared L3 cache of up to 256 MB. The Cuzco RISC-V processor has been implemented at 5-nm nodes with 8 execution pipelines and 7 million gates. It features an L2 configuration with 2MB and is targeted for a 2.5-GHz speed.

Figure 4 The Cuzco design represents the first in a new class of RISC-V CPUs aimed at data center-class performance while maintaining power efficiency and area benefits. Source: Andes

For the development of these RISC-V processors, the AndeSight integrated development environment (IDE) helps design engineers generate files for LLVM to recognize new instructions. Then there is AndesAIRE software, which facilitates graph-level optimization for pruning and quantization as well as back-end-aware optimization for fusion and allocation.

For OS support, the processors comply with RVA22 and RVA23 profiles and SoC hardware and software platforms. Andes also provides additional support to ensure that the Linux kernel is upstream-compatible.

Cuzco, unveiled at Hot Chips 2025 earlier this year, features a time-based out-of-order microarchitecture engineered to deliver high performance and efficiency across compute-intensive applications in AI, data center, networking, and automotive markets. Andes provided a preview of this out-of-order CPU at the RISC-V Summit.

Condor Computing developed the Cuzco RISC-V core, which is fully integrated into the Andes toolchain and ecosystem. Condor recently completed full hardware emulation of its new CPU IP while successfully booting Linux and other operating systems.

“Condor’s microarchitecture combines advanced out-of-order execution with novel hardware techniques to dramatically boost performance-per-watt and silicon efficiency,” Andes CTO Su said. “It’s ideally suited for demanding CPU workloads in AI, automotive compute, applications processing, and beyond.”

The first customer availability of the Cuzco RISC-V processor is expected in the fourth quarter of 2025.

The RISC-V adoption

According to Wawrzyniak, chip designers are now looking at both Arm and RISC-V processor architectures. “The RISC-V ISA and its rising ecosystem have interjected competition once again into the SoC design landscape.”

Furthermore, the custom RISC-V ISA extensions empower innovation and tailored performance. Not surprisingly, therefore, the adoption of RISC-V by large technology companies such as Broadcom, Google, Meta, MediaTek, Qualcomm, Renesas, and Samsung continues to validate the utility of the RISC-V ISA in the semiconductor industry.

RISC-V, once an academic exercise, has come a long way since its launch in May 2010 at the University of California, Berkley. However, as Krste Asanovic, chief architect at SiFive, said during his keynote, RISC-V will continue to evolve across different verticals and that it’ll be around for a long time.

Related Content

• Navigating the RISC-V Revolution in Europe
• RISC-V Summit spurs new round of automotive support
• RISC-V Exceeding Expectations in AI, China Deployment
• Why RISC-V is a viable option for safety-critical applications
• Why RISC-V + Blockchain Is the Conversation I’ve Been Waiting to Have

The post The next RISC-V processor frontier: AI appeared first on EDN.

Taiwan Semiconductor launches a new series of automotive-grade, low-loss diodes in three popular industry-standard packages. They provide an automotive-level performance upgrade in existing designs and low-power dissipation required for higher-power rectification applications.

(Source: Taiwan Semiconductor)

The 1,200-V PLA/PLD series, with ratings of 15 A, 30 A or 60 A, all feature low forward voltage (1.3 Vf max), low reverse leakage (<10 µA at 25°C), and high junction temperature (175°C Tj max). They are available in three packages—ThinDPAK, D2PAK-D, and TO-247BD—for design flexibility.

These 1,200-V diodes provide easy drop-in replacements using an industry-standard pinout to improve efficiency in existing designs, according to the company. They can be used in a variety of applications such as three-phase AC/DC converters, server and computing power (including AI power) systems, EV charging stations, on-board battery chargers, Vienna rectifiers, totem pole and bridgeless topologies, inverters and UPS systems, and general-purpose rectification in high-power systems.

The new PLA/PLD series is offered in six models manufactured to automotive-quality standards. Two of the models, the PLAD15QH (ThinDPAK) and PLDS30QH (D2PAK-D), are fully AEC-Q qualified for automotive applications. The other four models include the PLAD15Q (ThinDPAK), PLDS30Q (D2PAK-D), PLAH30Q (TO-247BD), and PLAH60Q (TO-247BD).

The PLA/PLD series are sampling now. They are in-stock at DigiKey and Mouser. Production lead times is 8-14 weeks ARO. Design resources include datasheets, spice models, Foster and Cauer thermal models, and CAD files (symbol, footprint, and 3D model).

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Bourns Inc. launches its series of Riedon precision wirewound resistors. These passive devices meet application requirements for high accuracy and long-term stability. They offer a wide resistance range of up to 6 megohms (MΩ) with ultra-low resistance tolerances (as low as ±0.005 percent).

(Source: Bourns Inc.)

This rugged, high-precision resistor series is offered in multiple axial, radial, and square package sizes and in a variety of lead configurations for greater design flexibility. They feature non-inductive multi-Pi cores, protective encapsulation technology, and a low standard temperature coefficient of ±2 ppm/°C.

These features help minimize inductance and noise while maintaining stability and efficiency even under high heat and harsh electrical conditions, Bourns said.

The series is 100 percent acceptance tested and RoHS-compliant. Applications include measurement equipment, bridge circuits, load cells and strain gauges, imaging systems, current sensing equipment, and high-frequency circuit designs.

The Riedon wirewound resistors are available now. Custom solutions are also available to meet specific customer requirements.

Last year, Bourns expanded its Riedon power resistor family with the launch of 11 product series, including wirewound resistors and current-sense resistors. They feature high power ratings, low temperature coefficients (TCRs), a wide resistance range, and an extended temperature range.

These resistors are available in numerous packaging options, including wirewound through-hole and surface mount; surface-mount metal film; and bare/coated metal element resistors. They target a variety of applications, including battery energy storage systems, industrial power supplies, motor drives, smart meters, telecom 5G remote radio and baseband units, and current sensing.

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According to Sony, the IMX828 CMOS image sensor is the industry’s first to integrate a MIPI A-PHY interface for connecting automotive cameras, sensors, and displays with their ECUs. The built-in serializer-deserializer physical layer removes the need for external serializer chips, enabling more compact, lower-power camera systems.

The IMX828 offers 8-Mpixel resolution (effective pixels) and a 150-dB high dynamic range. Its pixel structure achieves a high saturation level of 47 kcd/m², allowing accurate recognition of high-luminance objects such as red traffic signals and LED taillights.

A low-power parking-surveillance mode detects motion to help reduce theft and vandalism risk. Images are captured at low resolution and frame rate to keep power consumption under 100 mW. When motion is detected, the sensor alerts the ECU and switches to normal imaging mode.

Sony plans to obtain AEC-Q100 Grade 2 qualification before mass production begins. The IMX828 meets ISO 26262 requirements, with hardware metrics conforming to ASIL-B and the development process to ASIL-D. Sample shipments are expected to start in November 2025. A datasheet was not available at the time of this announcement.

Sony Semiconductor Solutions 

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NXP’s battery management chipset integrates electrochemical impedance spectroscopy (EIS) to enable lab-grade vehicle diagnostics. The system comprises three devices: the BMA7418 18-channel Li-Ion cell controller, BMA6402 communication gateway, and BMA8420 battery junction box monitor. Together, they deliver hardware-based synchronization of all cell measurements within a high-voltage battery pack with nanosecond precision.

By embedding EIS directly in hardware, the chipset supports real-time, high-frequency monitoring of battery health. Accurate impedance measurements, combined with in-chip discrete Fourier transformation, help OEMs manage faster and safer charging, detect early signs of degradation, and simplify overall system design.

EIS sends controlled excitation signals through the battery and analyzes frequency responses to reveal cell aging, temperature shifts, or micro shorts. NXP’s system uses an integrated excitation source with a pre-charge circuit, while DC link capacitors provide secondary energy storage for greater efficiency.

The complete BMS solution is expected to be available by the beginning of 2026, with enablement software running on NXP’s S32K358 automotive microcontroller. Read more about the chipset here.

NXP Semiconductors 

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Housed in a 6-pin, 2.0×1.6-mm LGA package, Mixed-Signal Devices’ MS1180 crystal oscillator conserves space in AI data center infrastructure. Factory-programmed to provide any frequency from 10 MHz to 1000 MHz with under 1-ppb resolution, it is well-suited for 1.6T and 3.2T optical modules, active optical cables, active electrical cables, and other size-constrained interconnect devices.

The MS1180 is optimized for key networking frequencies—156.25 MHz, 312.5 MHz, 491.52 MHz, and 625 MHz—and maintains low RMS phase jitter of 28.3 fs to 43.1 fs when integrated from 12 kHz to 20 MHz. It offers ±20-ppm frequency stability from –40 °C to +105 °C. Power-supply-induced phase noise is –114 dBc for 50-mV supply ripples at 312.5 MHz, with a supply-jitter sensitivity of 0.1 fs/mV (measured with 50-mVpp ripple from 50 kHz to 1 MHz on VDD pin).

Supporting multiple output formats (CML, LVDS, EXT LVDS, LVPECL, HCSL), the device runs from a single 1.8- V supply with an internal regulator.

The MS1180 crystal oscillator is sampling now to strategic partners and Tier 1 customers. Production volumes are expected to ramp in Q1 2026.

MS1180 product page   

Mixed-Signal Devices  

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A bit-level retimer from Diodes, the PI2DPT1021Q enables high-speed USB and DisplayPort (DP) connectivity in automotive smart cockpits and infotainment systems. The 10-Gbps bidirectional device supports USB 3.2 and DP 1.4 standards for various automotive USB Type-C applications.

The retimer has 4:4 channels, configurable via I²C for different modes: four-lane DP, two-lane DP with one-lane USB 3.2 Gen 2, or one- or two-lane USB 3.2 Gen 2. It is AEC-Q100 Grade 2 qualified and operates over a temperature range of -40° to +105 °C.

To maintain signal integrity, the PI2DPT1021Q offers receiver adaptive equalization that compensates for channel losses up to -23 dB at 5 GHz. It also provides low latency (<1 ns) from signal input to output, ensuring good interoperability between USB and DP devices. Additional features include jitter cleaning, an adaptive continuous-time linear equalizer (CTLE), and a 3-tap transmitter with selectable adjustment.

The PI2DPT1021Q retimer costs $1.65 each in lots of 5000 units.

PI2DPT1021Q product page 

Diodes

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ST’s VIPerGaN50W houses a 700-V GaN power transistor, flyback controller, and gate driver in a compact 5×6-mm QFN package. The quasi-resonant offline converter delivers up to 75 W from high-line input (185–265 VAC) or 50 W across the full universal input range (85–265 VAC). It uses a proprietary technique that ensures chargers and power supplies operate silently at all load levels.

Along with zero voltage switching (ZVS), the VIPerGaN50W includes dynamic blanking time, which minimizes switching losses by limiting the frequency. It also offers adjustable valley synchronization delay to maximize efficiency at any input line and load condition. A valley-lock feature stabilizes skipped cycles to prevent audible switching noise.

At no load, the converter’s standby power drops below 30 mW thanks to adaptive burst mode, helping meet stringent ecodesign regulations. Advanced power-management features ensure the output-power capability and switching frequency remain stable, even when the supply voltage changes.

In production now, the VIPerGaN50W is priced from $1.09 each in lots of 1000 units.

VIPerGaN50W product page

STMicroelectronics

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The adoption of RISC-V with open standards in automotive applications continues to accelerate, leveraging its flexibility and scalability, particularly benefiting the automotive industry’s shift to software-defined vehicles. Several RISC-V IP core and development tool providers recently announced advances and partnerships to drive RISC-V adoption in automotive applications.

In July 2025, the first Automotive RISC-V Ecosystem Summit, hosted by Infineon Technologies AG, was held in Munich. Infineon believes cars will change in the next five years more than in the last 50 years, and as traditional architectures come to their limit, RISC-V will be a game-changer, enabling the collaboration between software and hardware.

(Source: Adobe Stock)

However, RISC-V adoption will require an ecosystem to deliver new technologies for the automotive industry. The summit showcased RISC-V solutions and technologies ready for automotive, particularly for SDVs, bringing together RISC-V players in areas such as compute IP, software, and development solutions.

Fast-forward to October with several RISC-V players expanding the enabling ecosystem for automotive with key collaborations ahead of the October 2025 RISC-V Summit. Quintauris, for example, announced several partnerships, including with Andes Technology Corp., Everspin Technologies, Tasking, and Lauterbach GmbH, all focused on advancing RISC-V for automotive and other safety-critical applications.

The Quintauris strategic partnership with Andes, a provider of RISC-V processor cores, brings Andes’s RISC-V processor IP into Quintauris’s RISC-V-based portfolio, consisting of profiles, reference architectures, and software components. The partnership will focus on automotive, industrial, and edge computing applications. It kicks off with the integration of the 32-bit ISO 26262–certified processor in the AndesCore processor series with Quintauris’s automotive real-time reference architecture.

Quintauris is also teaming up with Everspin to bring its advanced memory solutions—magnetoresistive RAM technologies—into Quintauris’s reference architectures and real-time platforms for automotive, industrial, and edge applications. This partnership addresses the need for memory subsystems to meet the high standards for performance and functional safety in automotive applications.

In the development tools space, Quintauris announced a new partnership with Tasking to bolster RISC-V development in the automotive industry. Delivering certifiable development tools for safety-critical embedded software, Quintauris will integrate Tasking’s RISC‑V compiler into its upcoming RISC‑V reference platform.

Addressing embedded systems debugging, the new Quintauris and Lauterbach collaboration focuses on safety-critical industries such as automotive. Under the partnership, Lauterbach’s TRACE32 toolset, including a debug and trace suite, for embedded systems will be integrated into the Quintauris RISC-V reference platform. The TRACE32 toolset provides debugging, traceability, and system analysis tools.

Lauterbach also announced in October that its TRACE32 development tools support Tenstorrent’s system-on-chips (SoCs) and chiplets for RISC-V and AI-based workloads in the automotive, client, and server sectors. Tenstorrent’s automotive and robotics base die SoC targets automotive applications in SDVs. The SoC implements at least eight 64-bit superscalar, out-of-order TT-Ascalon RISC-V cores with vector and hypervisor ISA extensions, along with RISC-V-based AI accelerators and additional RISC-V cores for system and communication management.

The TRACE32 development tools allow simultaneous debugging of the TT-Ascalon RISC-V processors and other cores implemented on the chip, from pre-silicon development to prototyping on silicon and in-field debugging on electronic control units.

Also helping to accelerate the global adoption of RISC-V, Tenstorrent and CoreLab Technology are collaborating on an open-architecture computing platform for automotive edge and robotics applications. The Atlantis computing platform addresses demanding AI computing requirements, delivering a scalable, safety-ready CPU IP portfolio. The platform will leverage Tenstorrent’s RISC-V CPU IP and CoreLab Technology’s energy-efficient IP and SoC solutions.

Designed to deliver on performance, power efficiency, low total cost of ownership, and customization, all RISC-V CPU cores in the platform support deep customization, enabling customers to tailor their compute resources for their applications, according to Tenstorrent.

The automotive industry demands that ecosystem players meet stringent functional safety and security standards. To meet these requirements, Codasip recently announced that two of its high-performance embedded processor cores, the Codasip L735 and Codasip L739, have received TÜV SÜD certification for functional safety.

The L735 is certified up to ASIL-B and the L739 is certified up to ASIL-D, defined by the ISO 26262 standard. Both products are also compliant with ISO/SAE 21434 for cybersecurity in automotive development. In addition, Codasip’s IP development process is certified to both ISO 26262 and ISO/SAE 21434.

The L735 and L739 cores are part of the Codasip 700 family. The L735 includes safety mechanisms such as error-correcting code on caches and tightly coupled memories, a memory protection unit, and support for RISC-V RERI to provide standardized error reporting. The L739 adds dual-core lockstep, enabling ASIL-D certification.

Capability Hardware Enhanced RISC Instructions (CHERI) variants are available for both products. CHERI security technology protects against memory safety vulnerabilities. Codasip is standardizing a CHERI extension for RISC-V in collaboration with other members of the CHERI Alliance.

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A classic nonlinear analog function is the squaring circuit. It’s useful in power sensing, frequency multiplication, RMS computation, and many other odd jobs around the lab bench.

The version in Figure 1 is straightforward, fast, temperature-compensated, calibration-free, and if the transistors are well matched, accurate. The final output is as follows:

 Vout = R3 antilog(2log(Vin/R1) – log(Vgain/R2)) = R3 antilog(log((Vin/R1)2 /(Vgain/R2))
Vout = (R1-2 R2 R3)Vin2 /Vgain

Figure 1 The squaring amplifier that is fast, temperature-compensated, calibration-free, and accurate (if the transistors are well matched).

Wow the engineering world with your unique design: Design Ideas Submission Guide

Its input can accept either voltage or current. It gains a bit of extra versatility from a separate gain factor control input, which can also accept voltage or current. Another boost in versatility comes from a similarly flexible output with both voltage and (inverted) current output mode. If the current mode is chosen, A3 and R3 can be omitted and a dual op-amp (OPA2228) used instead of the quad (OPA4228) illustrated.

 The series connection of Q1 and Q2 generates a signal proportional to 2log(Vin/R1) = (log(Vin/R1)2). This is applied to antilogger Q3 ,which subtracts log(Vgain/R2) from it to generate a current of:

-(antilog(log((Vin/R1)2 /(Vgain/R2))

This is inverted and scaled by R3 and A3 to yield the final:

Vout = (R1-2 R2 R3)Vin2 / Vgain

 Note that if the three resistors are equal and Vin = Vgain, then:

Vout = (R-2 R R)Vin2 / Vin = Vin

And, the squarer circuit will have unity gain.

Which is kind of a “square deal,” although I doubt it’s what Teddy Roosevelt had in mind when he made that phrase his 1904 campaign slogan.

An interesting application happens when the squarer is combined with a full-wave precision rectifier (like the one in “New full-wave precision rectifier has versatile current mode output”). See Figure 2.

Figure 2 The cascading full-wave rectifier (black) with squarer makes low distortion frequency doubler (red).

 Stephen Woodward’s relationship with EDN’s DI column goes back quite a long way. Over 100 submissions have been accepted since his first contribution back in 1974.

Related Content

• New full-wave precision rectifier has versatile current mode output
• Simple diff-amp extension creates a square-law characteristic
• Boost and modify square waves: More circuits
• Precision Full Wave Rectifier Circuit

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For the past couple of years, I’ve been using AI to assist in the design of my hardware and firmware projects. The experience has generally been good, even though the outcome isn’t always useful. So, I’m presenting a short summary of a few of the tasks I have attempted and providing my unscientific grade to the outcome. The grades will be averaged at the end. Note: I do not have any paid AI subscriptions—I only used free AI tools, mostly Microsoft Copilot and ChatGPT (although I have tried a few others). These are just a few of my experiences using online AI.

Do you have a memorable experience solving an engineering problem at work or in your spare time? Tell us your Tale

Converting voltage to percent charge

Grade: A

I wanted to show the charge remaining in a lithium polymer battery used to power a design. This is not straightforward as the function to convert voltage to percent charge for a lithium polymer battery is not a linear function. I asked Copilot to make a table of 20 voltages from 3.2 V to 4.2 V and their respective charge percentages. Then I asked it to create a C function to do this conversion. It created this nicely, including linear interpolation.

Finding the median without sorting

Grade: D

A while back, I wrote a Design Idea (DI) article on non-linear filters. While doing this, I queried Copilot to create a C program that can find the median of 5 numbers and do this without sorting. (No sorting for a small number of points is useful for increasing speed.) It created a nice-looking program—nice formatting and good comments. It also compiled fine. The problem was that the program didn’t work—it found the wrong value for the median in some cases.

Initializing an ADC

Grade: C+

Another project required me to write code for the SAMD51 MCU to initialize the ADC for high-speed sampling. As I was trying to get maximum speed from the ADC, it was a somewhat complex setup, especially the clocking system. I tried creating the code in both Copilot and ChatGPT multiple times.

Some code would not compile due to things like bad register names, and some code would just not work, giving no ADC readings. After some back and forth, those issues were corrected. A few of the comments in code were misleading or just plain wrong as it applied to clock frequencies. As the code got close to a working function, I took over the code and reworked parts of it to make it work.

Graphic design

Grade: C+

I was doing some LCD graphics design for a project, and one part was a battery charge indicator. This symbol, for battery percent of charge, was to be displayed on an LCD with an ILI9321 controller. (This standard figure looks like an AA battery with a green interior representing the percent charge.)

I asked Copilot to write C code for this using the GFX graphics library. The length of the green fill worked well, but the battery figure looked nothing like a battery. It was a rectangle with two large circles on both ends. I had to rewrite portions of the code myself.

Grade: F

In the same project, I asked Copilot for a USB symbol written using the GFX graphics library, as above. This didn’t look like the trident-like, universal USB symbol. I was essentially three sticking out from a central point at various angles. It was unusable.

Enclosure design

Grade: D-

Next, I tried to have Copilot and ChatGPT design an enclosure that would work on a workbench, allowing the user to see the LCD and to easily connect BNC cables. All I got were images of rectangular boxes. No matter how I asked for a more unique shape, it never went much beyond a rectangular enclosure. Then, even the rectangular box could not be delivered as a usable 3D file “step”, “stl” file without using other programs.

Filter design

Grade: C-

I asked ChatGPT, “Can you design and display a circuit that takes in a signal, AC couples it to a gain stage of 5, and then filters it at 120 kHz before outputting it?” Instead of explaining the result, the image in Figure 1 will speak for itself.

Figure 1 ChatGPT’s output for a filter design that takes in a signal, AC couples it to a gain stage of 5, and then filters it at 120 kHz before outputting it.

It did include a nice explanation of how components were selected, but the schematic was mostly unreadable. Dedicated tools such as TI’s Webench filter design tool, Analog Devices’ Filter Wizard, and ST’s eDesign Suite are the right tools for filter circuit design and are actually easier to use.

Grade: Ungraded

I tried to create C code, in both Copilot and ChatGPT, for calculating coefficients for a digital Sallen-Key 2-pole high-pass, low-pass, band-pass, and band-stop filters. I tried many times and could not get a good working algorithm. The code was close, but the filters did not function correctly. Eventually, I found the code after an extensive Google search. It’s possible my testing may have been part of the problem—unsure.

Grade: B

Along the way, I tried lots of smaller queries, many of which were very helpful.

A lab notebook

I’m sure some of the issues are my skill in creating the AI prompts. This certainly made my attempts take longer as I had to add more detail in follow-up prompts. I actually found this conversational style more engaging than using search engines. It’s not like a Google search, where you can’t typically do follow-ups to your query—you have to re-enter your original query with a modification.

The AI systems work much more like a conversation with a colleague. You can tell it that the code it gave you did not compile, as it didn’t recognize a register name. Or you can ask it to give you faster code, or change a resistor value in a circuit, and recalculate the remaining components.

One thing I learned when writing this article is that both ChatGPT and Copilot keep a complete history of conversations we had. It’s sort of like a lab notebook, showing your path to a certain design—very helpful.

A C rating

Looking at the average grade, it comes in between a C and a C-. I’ll give it the benefit of the doubt and call it a C. The C rating matches my gut feel also. The interaction is fairly easy—it feels like interacting with a coworker. The conversation goes on, attempting to fine-tune the final answer. The interaction process is much better than doing a Google search and getting a list of things to pick from, without an easy way to refine the search.

Does it save time? That’s hard to judge as I’m still learning how to create better prompts. Sometimes I get a useful answer right away. On more complex queries, I’ve gotten pulled down a rabbit hole and wasted time while the solution diverged from what I was looking for. There have been times when it had me trying to finetune the result, and I turned to Google and got an answer much faster.

You can easily be lulled into the feeling that you’re conversing with a savant, but it may be more like AI-splaining. Every answer exudes confidence, but it could be the confidence of ignorance. Remember that these answers have not been checked or tested.

Will I continue to use it? Certainly… I’ll get better at using it, and the tools will continue to improve. What I would like to see is an AI tool focused specifically on electrical engineering (hardware, firmware, and system design). This may focus its skills on finding or creating circuits, and being able to dig down deep into data sheets, etc. It would also be nice if it could test its results through simulation or by executing the code in a series of tests. Maybe in the future.

All in all, it’s worth using and everyone should give it a try, just check the answer closely.

Damian Bonicatto is a consulting engineer with decades of experience in embedded hardware, firmware, and system design. He holds over 30 patents.

Phoenix Bonicatto is a freelance writer.

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• Increasing bit resolution with oversampling
• How AI is changing the game for high-performance SoC designs

The post How help are free AI tools for electronic design? appeared first on EDN.

Many industrial applications in the automotive, automation, appliance, or medical sectors require power supplies that comply with functional safety standards. If the input voltage of such a power supply is not within its specification, the system to which it is supplying power is potentially operating in an unsafe state. Monitoring input and output voltages for faults such as undervoltage, overvoltage, and overtemperature may require resetting and transitioning the system to a safe state.

Defining the protections needed to comply with functional safety standards depends on the safety level, which the design engineer must determine in cooperation with a safety inspection agency such as Technischer Überwachungsverein. The engineer must also work on a time-consuming risk assessment of failures that address both safe and dangerous failures as well as random and systematic failures.

Functional safety in power supplies

Safety standards such as IEC 61508 or ISO 13849A specify the maximum allowable probability of dangerous failures per hour.

The requirements for a safe power supply as specified in IEC 61508, which covers functional safety in industrial manufacturing, include overvoltage protection with safety shutoff, secondary-side voltage control with safety shutoff, and power-down with safety shutoff. These protections require significant additional external circuitry around the switched-mode power supply (SMPS).

A safe power supply must also fulfill random hardware fault requirements. Using an integrated PG pin as the safety mechanism to monitor failures can be insufficient, because this pin is typically not independent; it shares the same internal band gap with all safety and monitoring features. A drifting band gap will cause the PG pin to fail. This is known as a common-cause failure, which does not meet functional safety requirements.

As shown in Figure 1, detecting any fault will also require additional supply-voltage supervisors as well as a switch connected in series to the input; alternatively, the switch could connect to the output. This switch disconnects the system from the source or load in case of a failure. Redundant supply-voltage supervisors monitor the input and output voltages. Typically, an industrial power supply is limited to less than a 60-VDC input, even in the event of a fault, requiring an additional circuit with transient voltage suppression and a fuse, because not all devices are specified to 60 V.

Figure 1 An industrial safe power supply example block diagram. Source: Texas Instruments

The switch at the input, which is under the control of the monitor, can remove power in case of a failure. The input and output voltage are monitored continuously. As I mentioned earlier, to comply with functional safety standards, all parts must operate within a specified operating voltage. That is not an easy task, given the requirement to detect undervoltage and overvoltage events immediately.

Buck converter

Using a functional-safety-compliant buck converter with integrated safety features can greatly reduce the amount of external circuitry, as shown in Figure 2. An integrated redundant circuit, which replaces the external voltage supervisor, has a startup diagnostic check and can detect the failure of a FET. This implementation reduces the overall cost of designing a safe power supply.

Figure 2 Integrated functional safety features replace an external voltage supervisor, reducing circuit complexity. Source: Texas Instruments

The nFAULT pin in the converter is used for overvoltage protection and as a failure flag. Triggering the nFAULT pin disables a safety switch, which in this case is an ideal diode controller connected to the input. The Temp pin communicates the temperature to a microprocessor and forces a shutdown if the temperature is too high. The VSNS pin has feedback path failure detection, and there is another feedback divider for redundancy. During startup, the LM68645-Q1 buck converter checks the configuration on the RT, FB, and VSNS pins.

Figure 3 shows a block diagram of a universal board (configurable to meet different safety standards)—with an input voltage range of 19.2 V to 28.8 V and a maximum 60 V—for a safe power supply.

A synchronous buck converter generates a 5-V output with a maximum current of 3 A. Beside the buck converter is an ideal diode with back-to-back MOSFETs connected to the input. An ideal diode connects to the output. The nFAULT pin can control both switches. Two additional supervisors for redundant voltage monitoring on the input and output can disable both switches as well. The ideal diode controller has power-path control and overvoltage protection. The voltage supervisors also provide built-in self-test and overvoltage and undervoltage protection.

Figure 3 The TI Industrial 24 V to 5 V safe power supply reference design, where a number of redundant options on the board make it possible to comply with different functional safety standards. Source: Texas Instruments

A buck converter designed to help meet functional safety standards reduces the amount of necessary functional safety documentation, system cost, and time to market. Because all of the devices in the 24 V to 5 V safe power supply reference design are specified for ≥ 60 V, an input transient voltage suppressor or fuse is not necessary.

Upgrading a safe power supply

Although upgrading a safe power supply to a higher standard requires significant effort, it is possible to design a power supply that meets functional safety requirements but also decreases time to market and system cost. Using a buck converter with integrated safety features helps achieve systematic and random hardware metrics and reduces the needed external circuitry.

Florian Mueller, systems applications engineer, Texas Instruments

Related Content

• Attaining functional safety: Managing random failures
• Motor control for functional safety
• Enabling functional safety in automotive processors
• Designing power supplies for industrial functional safety, Part 1
• Approaches to functional safety in automotive design

 

 

The post Power Tips #146: Design functional safety power supplies with reduced complexity appeared first on EDN.

Polyn Technology Ltd. announces the successful manufacturing and testing of its first silicon-implementation of its neuromorphic analog signal processing (NASP) technology. It includes the validation of both the NASP technology and design tools, which automatically convert trained digital neural network models into ultra-low-power analog neuromorphic cores ready for manufacturing in standard CMOS processes. The first product chip features an analog neuromorphic core of a voice activity detection (VAD) neural network model.

(Source: Polyn Technology Ltd.)

This platform uses trained neural networks in the analog domain to perform AI inference with much lower power consumption than conventional digital neural processors, according to the company. Application-specific NASP chips can be designed for a range of edge AI applications, including audio, vibration, wearable, robotics, industrial, and automotive sensing.

This is the first time that Polyn generated an asynchronous, fully analog neural-network core implementation in silicon directly from a digital model. This opens up a “new design paradigm— neural computation in the analog domain, with digital-class accuracy and microwatt-level energy use,” said Aleksandr Timofeev, Polyn’s CEO and founder, in a statement.

Targeting always-on edge devices, the NASP chips with AI cores process sensor signals in their native analog form in microseconds, using microwatt-level power, which eliminates all overhead associated with digital operations, Polyn explained.

Recommended Neuromorphic analog signal processor aids TinyML

The first neuromorphic analog processor contains a VAD core for real-time voice activity detection and offers fully asynchronous operation. Key specs of this NASP VAD chip include ultra-low-power consumption of about 34 µW during continuous operation and ultra-low latency at 50 microseconds per inference.

In addition to the VAD core, Polyn plans to develop other cores for speaker recognition and voice extraction, targeting home appliances, communications headsets, and other voice-controlled devices.

In April 2022, the company announced its first NASP test chip, implemented in 55-nm CMOS technology, demonstrating the technology’s brain-mimicking architecture. This was followed in October 2022 with the introduction of the NeuroVoice tiny AI chip, delivering on-chip voice extraction from any noisy background. In 2023, Polyn introduced VibroSense, a Tiny AI chip solution for vibration monitoring sensor nodes. (Polyn was ranked as an EE Times Silicon 100 company to watch in 2025.)

Customers who are developing products with ultra-low-power voice control can apply online for the NASP VAD chip evaluation kit. Polyn will demonstrate its first NASP chips, available for ordering, at CES 2026 in Las Vegas, Nevada, January 6-9, in Hall G, Booth #61701. A limited selection will be showcased at CES Unveiled Europe in Amsterdam, October 28, Booth HB143.

The post Polyn delivers silicon-implementation of its NASP chip appeared first on EDN.

Printed-circuit boards (PCBs) are an integral part of most electronic devices today, and as PCBs become smaller, electronics engineers must remain aware of the tiny defects that can affect how these components function, especially when they involve high-frequency signals. Surface roughness may seem minor, but it can significantly affect PCB performance, including impedance and signal transmission. What should electronics engineers know about it, and how can they minimize this issue?

Path length

Rough PCB surfaces increase the signal’s path length. This is due to the skin effect, which occurs because high-frequency electrical signals are more likely to flow along a conductor’s outer surface instead of through its core. A longer path length can also increase resistance and cause energy loss.

(Source: Adobe Stock)

Engineers can reduce these issues by choosing the appropriate surface finishes for different PCB parts. Immersion silver is a good choice for balancing performance and affordability, although it must be handled carefully to prevent tarnishing.

Electroless nickel immersion gold offers a flat and smooth surface with a gold layer that promotes excellent solderability and conductivity and a nickel layer that offers oxidation protection. This surface finish minimizes signal distortion, making it a popular option for microwave and radio-frequency applications.

Although immersion tin features a smooth surface, it has lower corrosion resistance than other options, making it less frequently selected for high-frequency PCBs. Because hard gold has good conductivity and resists wear, engineers often use it in high-frequency applications, such as on contact points and connectors. This approach minimizes signal loss and increases overall durability.

If you plan to outsource finishing or other manufacturing steps to a specialty provider, consider choosing one with extensive experience and the equipment and expertise needed for your PCB design.

For example, in 2024, PCB company OKI Circuit Technology created an ultra-high, multilayer PCB line. This expansion boosted its capacity potential by approximately 1.4× while also helping the company cater to customers with smaller orders. The company has also invested in numerous enhancements that increase its precision and equip it to meet the needs of next-generation communications, robotics, and semiconductors.

Signal integrity

Rough surfaces compromise signal integrity and can cause parasitic capacitance. This issue can also increase crosstalk if it results in uneven electromagnetic field distribution. Smoother surfaces enable faster signal speeds while preventing distortion and delays.

Because surface roughness is one of many factors that can interfere with signal integrity, electronics engineers should scrutinize all design aspects to find other potential culprits. Some companies offer specialized tools to make the task easier.

One provider sells software that uses artificial intelligence to assess proposed designs. Users can also check trace path routing by studying cross-sectional diagrams that show various layers, identifying potential issues more quickly.

Component placement and PCB layout configurations can affect signal integrity, so designers should consider those aspects before assuming rough surfaces have degraded performance. Digital twins and similar tools allow engineers and product designers to experiment with various layouts before committing to a final PCB layout. Keeping a log of all design changes also allows engineers to revert to previous iterations if newer versions worsen signal integrity.

If companies notice ongoing signal integrity problems or other challenges, examining the individual industrial processes may highlight the causes. This usually starts with data collection because the information provides a baseline. Once companies begin tracking trends, they can discover the most effective ways to tighten quality control and meet other goals that improve PCB performance.

Tailored assistance

If electronics engineers conclude that rough surfaces are among the primary contributors to signal issues in their high-frequency PCBs, they can then address the problem by partnering with third-party providers that understand the complexities of finishing small parts. These companies can detail the various finish types available and provide pricing and lead times, depending on the unit order of PCBs.

Companies that need PCB finishing for prototypes or small production runs may request manual processes. Skilled technicians use tools and magnification on parts with complex geometries or other characteristics that make them unsuitable for mechanical methods.

Controlled combustion, electrolytic action, and vibratory containers are some of the other options for finishing small parts through non-manual means. Specialist finishers can examine the PCB designs and recommend the best strategies to achieve consistent smoothness with maximum efficiency.

Because many manufacturers have high-volume finishing needs, some startups have emerged to fill the need while supporting producers’ automation efforts. Augmentus is one example, focusing on physical AI to scale automated surface finishing for high-mix environments. The company has built a fully autonomous system for today’s factory floors. In July 2025, the company secured $11 million in a Series A+ funding round to scale for high-mix, complex robotic surface finishing and welding.

Augmentus views surface finishing as one of the most challenging problems in automation, but the company believes its technology will break new ground. Although it is too early to know how this option and others like it may change PCB production, automated processes could offer better repeatability, making surface roughness less problematic.

Ongoing awareness

Because surface roughness can negatively affect high-frequency PCB signals, engineers should explore numerous ways to address it effectively. Considering this issue early in the design process and selecting appropriate finishes are proactive steps for strengthening component quality control.

About the author

Emily Newton is a technical writer and the editor-in-chief of Revolutionized. She enjoys researching and writing about how technology is changing the industrial sector.

The post Are rough surfaces on PCBs impacting high-frequency signals? appeared first on EDN.

The ovens in this two-part Design Idea (DI) can’t even warm that leftover half-slice of pizza, let alone cook dinner, but they can keep critical components at a constant temperature. In the first part, we’ll look at a purely analog approach, saving something PWM-based for the second.

Perhaps you want to build a really wide-range LF oscillator with a logarithmic sweep, using no more than a resistor, an op-amp, and a diode for the log element. That diode needs to be held at a constant temperature for accuracy and stability: it needs ovening (if there is such a verb).

Wow the engineering world with your unique design: Design Ideas Submission Guide

I made such a device some years ago, and was reminded of it when spotting how a bead thermistor fitted rather nicely into the hole in a TO-220’s tab. (Cluttered workbenches can sometimes trigger interesting cross-fertilizations.) Now, can we turn that tab into a useful temperature-stabilized hotplate, suitable for mounting heat-sensitive components on? Ground rules: aim at a rather arbitrary 50°C, make the circuitry as simple as possible, use a 5-V supply, and keep the consumption low.

This is a practical exploration of how to use a transistor, a thermistor, and as little else as possible to get the job done. It lacks the elegance and sophistication of designs that use a transistor as both a sensor and a source of heat, but it is simpler.

Figure 1 shows the schematic of a simple version needing only a 2-wire connection, along with two photos indicating its construction. It was slimmed down from a more complex but less successful initial idea, which we’ll look at later.

Figure 1 A simple oven circuit, heated by both R2 and Q2. The NTC thermistor Th1 provides feedback, the set point being determined by R1. Note how critical components are thermally tied together as they are all built onto the TO-220 package, as shown in the photos. Also note the fine lead wires to reduce heat loss once the assembly is heat-insulated.

Both R2 and Q2 can contribute to heating. On a cold start (literally) Th1’s resistance is high so that the Darlington pair Q1 and Q2 has enough base voltage to saturate it, with (most of) the rail voltage across R2. As the assembly heats up, Th1’s resistance drops, reducing the drive to Q1/2. The rail now appears across both R2 and Q2, with the latter taking over as the main, though now reduced, source of heat. This gives a degree of proportional control, reducing the drive as the set-point is approached. That base drive depends not only on the ratio of R2 to Th1 but also on Q1/2’s effective VBE, which needs to be temperature-stabilized—as indeed it is. Consumption varies from ~90 mA when cold to ~30 mA when stable.

Setting and measuring the temperature

R1 sets the stabilization temperature, the target being 50°C. Experimentally, 12k worked best, giving a stable hotplate temperature of 49.6°C for an ambient of 19.5°C. Cooling the surroundings to -0.5°C left the hotplate at 48.8°C, so that the hotplate temperature falls by 0.04°C for each degree drop outside. Better thermal insulation would have reduced that.

The measuring probe was a 10k thermistor equipped with fine wires and stuck to the hotplate with thermal paste, the module being wrapped in ~12 mm of foam—and we’ll come back to that. Thermal paste and heat shrink could have been used for the main assembly but dabs of epoxy worked well and kept the hotplate surface flat. Metal-loaded, high-temperature epoxy conducts heat several times better than the plain-vanilla variety while still being an electrical insulator, though that may make little difference given reasonable physical contact.

Other resistors and transistors

R2 is fairly critical. A higher value than 47R heats up slower than is necessary, while a lower one does so too fast, leading to the temperature overshooting because of the limited proportional control. Experiments showed that 47R was close to optimal, with minimal overshoot and thus the fastest stabilization time. The hotplate temperature settles to within a degree in around two minutes and is almost spot-on after three minutes.

Neither Q1 nor Q2 is critical, but the E-line package of a ZTX300 (for example) fits better than a TO-92 would. But why not use an integrated Darlington like the TIP122? Alas, such devices incorporate base–emitter resistors, nominally 10k and 150R, which load Th1 unpredictably. Trying one picked at random showed that R1 needed to be ~7k8 for a set-point of 50°C.

Similarly, this also works with Q1/2 replaced by a MOSFET, with R1’s value now depending on the gate threshold; 3k9 was close for a BUK553. BJTs are far more predictable: build this as drawn, and it should be within a degree, with Q1/2’s VBE settling at ~1.18 V; use a random MOSFET, and it could be anywhere.

Access all areas

The next variant, shown in Figure 2, is electrically similar but provides access to useful circuit nodes to help monitor its performance. It was also easier to experiment with.

Figure 2 While electrically the same as Figure 1, this brings out most circuit nodes to help with experimentation and monitoring, including the LEDs on “pin 3”.

Now we can see what we’re doing! The LEDs give a simple status indication, the green one lighting when it’s close to the set-point rather than fully stable. Figure 3 shows the effect, along with traces for Q1/2’s Vcc—allowing us to read the current in the transistors and R2—and the hotplate temperature. The latter is accurate, but the voltage and current scales are less so because they assume a precise 5-V supply and a 50-Ω load rather than the measured 4.94 V and 47Ω plus stray resistance. This module stabilized at ~50.6°C.

Figure 3  Measurements taken from Figure 2’s circuit for about three minutes after a cold start.

So much for the basic circuit. Now, it needs thermal insulation to keep the heat in, a block of foam being the obvious choice. But foams have widely differing thermal conductivities. Expanded polystyrene or polyethylene will work, but the foamed polyisocyanurate or similar used for wall insulation panels is around twice as good—and offcuts are often freely available from builders’ skips/dumpsters! Figure 4 shows the module from Figure 2 mounted on/in a block of it, with at least 10 mm of foam around any part of the circuit module.

Wikipedia has an illuminating plot of the thermal conductivities of many materials, including our foams and epoxies. The article of which it is a part has a lot of useful background, too.

Figure 4 The module from Figure 2 mounted on a block of foam. The intermediate connecting wires are meandered across its surface to minimize heat loss. Note the diode, typical of a component needing stabilization, stuck to the hotplate, ready for its new connections to be treated similarly.

The fine lead wires—0.15 mm diameter, as used with wiring pencils—are meandered over the surface to lengthen the thermal paths. Copper has a thermal conductivity some 19,000 times greater than the foam: 384 W/m·K vs ~0.02 W/m·K. In very crude terms, for a given thermal path length and temperature gradient, a single, short 0.11-mm-diameter copper wire will leak heat at about the same rate as the entire surface area of our foam block (~6000 mm2). Ironically, perfect insulation would be bad, as the innards could never cool to recover from an overshoot. This build took 620 seconds to cool by 63% of the way to ambient.

Hot stuff

Disconnecting Th1 in Figure 2’s circuit let the module heat up to the max while still allowing monitoring—or would have done, had I not chickened out when its resistance dropped to 720 Ω, for just over 100°C. (The epoxy was rated to 110°C.) That was with the full insulation; in free air, it struggled to reach 70°C—the rating for other components.

One subtle problem is the inevitable mismatch between the sensing thermistor and the target device, as analyzed in a Stephen Woodward DI, which also implies that the position of the target on the hotplate will affect its actual temperature. We’ll ignore that for the moment, because we’re more interested in constancy than precision, but will return to it in Part 2.

Finishing at the starting point

The foregoing circuits were actually simplifications of my starting point, which is shown in Figure 5. When the temperature is stable at ~50°C, point A is at half-rail. R3 is chosen so that U1’s output will turn Q1/2 on just enough to maintain that. However, while the extra gain improves the temperature regulation, it also causes some overshoot. R3 or R2 must be trimmed to set the temperature: fiddly, and not really designable. R3 was calculated at 4k12 but needed ~5k6 in reality. That’s why I gave up on this approach.

Figure 5 The original circuit that suffered from overshoot. The LEDs give a too-high/too-low temperature indication.

The long-tailed pair of Darlingtons (Q3, Q4) sense the difference between the thermistor voltage—half the rail when stable, as noted—and a half-rail reference, so that the red LED will be on when the temperature is low, the green one lighting while it’s high, with both on at the stable point. Full-red to full-green takes ~300 mV differential, or ~±3°C. This works but gives no better indication than the LEDs in Figure 2. (The low-power Darlingtons used seem to omit those extra, internal resistors. Q1/2 could now be replaced by that TIP122, as it’s driven by a low-impedance source. R4 is purely to protect against current surges.)

Figure 6 plots its performance when starting from cold, showing the overshoot and recovery. Compare this with Figure 3.

Figure 6 The start-up performance of Figure 5’s circuit.

If I were building something similar in any quantity, I wouldn’t do it like this: SMDs and a flexible circuit would be much cleaner. For example, a 2512 power resistor for R2 (or R5 in Figure 5), pressed flat, with some insulation, against the power transistor’s tab would probably be ideal.

In Part 2, we’ll see how even a simple PWM-based circuit can give better proportional control and hence generally better performance. The bad news: we may eventually abandon the TO-220 tab in favor of another way of assembling our hotplate.

Related Content

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• Dropping a PRTD into a thermistor slot—impossible?

The post 5-V ovens (some assembly required)—part 1 appeared first on EDN.

Trailing-edge dimmers offer smoother, quieter control for modern lighting systems—but their inner workings often remain overlooked. This post sheds light on the circuitry behind the silence. Sometimes, the most elegant engineering hides in the fade, where silence is not a flaw but a feature.

Let’s get started.

Dimmers serve as an effective interface for controlling energy-efficient lighting systems. And dimming methodologies are broadly categorized into forward-phase dimming (leading-edge), reverse-phase dimming (trailing-edge), and four-wire dimming, commonly referred to as 0–10 V analog dimming.

This post specifically examines reverse-phase dimming, also known as trailing-edge dimming, which is particularly well-suited for electronic low-voltage (ELV) transformers and modern LED drivers. Its smoother voltage waveform and inherently lower electromagnetic interference (EMI) make it ideal for applications requiring silent operation and compatibility with capacitive loads.

Leading and trailing edge dimming

In a leading-edge dimmer—also known as a triac dimmer or incandescent dimmer—the electrical current (sinusoidal signal) is interrupted at the beginning of the AC input waveform, immediately after the zero crossing. This dimming method is traditionally used with incandescent lamps or magnetic low-voltage transformers.

On the other hand, a trailing-edge dimmer interrupts the current at the end of the AC input waveform, just before the zero crossing (Figure 1). This technique is better suited for electronic drivers or low-voltage transformers with capacitive loads.

Figure 1 In trailing-edge dimming waveform, conduction begins mid-cycle, and current is interrupted before zero crossing to suit capacitive loads. Source: Author

In a nutshell, a trailing-edge dimmer is an electrical device used to adjust the brightness of lights in a room or space. It operates by reducing the voltage supplied to the light source, resulting in a softer, dimmer glow.

Unlike leading-edge dimmers—which cut the voltage at the beginning of each AC waveform—trailing-edge dimmers reduce the voltage at the end of the waveform. This “trailing edge” approach enables smoother, more precise dimming, especially at lower brightness levels.

Trailing-edge dimmers are particularly well-suited for LED lighting. They tend to be more efficient, generate less heat, and offer better compatibility with modern electronic drivers. The result is a quieter, flicker-free dimming experience that feels more natural to the eye.

Figure 2 The popular DimEzy brand for trailing-edge rotary dimmers embodies compact engineering optimized for retrofit installations. Source: LiquidLEDs

It’s important to note that most mains-powered LED bulbs are not dimmable. Even among those labeled as dimmable, compatibility with dimmer types can vary. Many require dedicated trailing-edge dimmers to function correctly; using the wrong dimmer may lead to flickering, limited dimming range, or even premature failure. Always check the bulb’s specifications and pair it with a suitable dimmer for reliable, smooth performance.

Moreover, since LED bulbs and dimmers are mains-operated, even minor mishandling can lead to electric shock or fire hazards. Always choose compatible components and follow safety guidelines.

Trailing-edge dimmer design: The starting point

Building a trailing edge dimmer is not trivial; but it’s far from overcomplicated. Below is a conceptual block diagram for those poised at the starting line.

Figure 3 A conceptual block diagram highlights the key functional units coordinating trailing-edge dimming. Source: Author

From the block diagram above, several distinct functional stages interact with each other to perform the overall dimming functionality. In a trailing-edge dimmer circuit, the power supply delivers a stable low-voltage DC source to power control and switching stages. The zero-crossing (ZC) detector pinpoints the exact moment the AC waveform crosses zero volts, providing a timing reference for phase control.

Based on this, the timing control block calculates a delay to determine when to switch off the load during each half-cycle, shaping the trailing edge of the waveform. This delayed signal is then fed to the gate driver, which conditions it to reliably switch the power MOSFETs, the primary switching elements that interrupt current partway through each cycle, enabling smooth dimming with minimal noise and flicker.

So, for your trailing-edge dimmer, the selection of components involves careful consideration of their roles in the dimming process.

• Power supply (DC): This supply will power the control circuitry, including the digital logic and gate drivers. Its voltage and current rating must be sufficient to reliably operate these components, especially under varying load conditions.
• Zero-crossing (ZC) detector: This detector is fundamental for timing the dimming cycle. It senses when the AC waveform crosses zero, providing a synchronization point. The ZC detector should be fast and accurate to ensure precise dimming.
• Timing control: This element, often integrated with digital logic, dictates the duration for which the power MOSFET remains on during each AC half-cycle. For trailing-edge dimming, the gate pulse is enabled at the ZC signal and disabled after a specific ON-time pulse width.
• Digital logic: This is the brain of the dimmer, interpreting user input—for instance, from a potentiometer or button—and controlling the timing logic. It might involve simple logic gates or a microcontroller. One document mentions a triple 3-input NOR gate for control, indicating the use of basic digital logic.
• Gate drivers: Gate drivers are essential for efficiently switching power. They provide the necessary current and voltage levels to turn the MOSFETs on and off quickly, minimizing switching losses and heat generation. Proper selection ensures a clean gate drive signal.
• Power MOSFETs: The power MOSFET acts as the main switching element, controlling the power delivered to the load. It must be chosen based on the load’s voltage and current requirements, with low on-state resistance (Rdson) for efficiency and adequate heat dissipation capabilities. For AC dimming, devices capable of handling the AC voltage and current, such as specific MOSFETs or IGBTS designed for phase control, are necessary.

Recall that a trailing-edge dimmer operates using transistor switches that begin conducting at the start of each half sine wave. These switches remain active for a defined conduction angle, after which they turn off, effectively truncating the AC waveform delivered to the load.

This approach results in smoother current transitions. The electronic load benefits from the gentle rise of the sine wave, and once the switch turns off, any residual energy stored in inductive or capacitive components naturally dissipates to zero. This behavior contributes to quieter operation and improved compatibility with sensitive electronic loads.

Up next is the practical schematic of a trailing edge phase control rotary wall dimmer designed without a microcontroller and originally introduced by STMicroelectronics over a decade ago.

Although this elegant concept now calls for a few updates—mainly due to the unavailability of certain key components (fortunately, drop-in replacements exist)—it remains an invaluable design reference, at least to me. I could not have expressed it better myself, so here is the link to its full documentation.

Figure 4 Rotary wall dimmer circuit employs reverse-phase control to regulate mixed lighting loads. Source: STMicroelectronics

Happy dimming

In summary, there is not much more to add regarding trailing-edge dimmers for now. However, it’s worth noting that these dimmers can also be built using a microcontroller, which is especially useful for smart lighting systems. Compared to specialized dimmer ICs, microcontrollers provide more freedom to create custom dimming profiles, incorporate user interfaces, and connect with smart home technologies like Wi-Fi or Bluetooth.

That is all for now. But don’t let the dimming stop here.

Dive deeper into the fascinating world of trailing-edge dimmers. Experiment with different component combinations, explore their impact on dimming performance, and share your discoveries with us.

What will you create next? Let’s know your thoughts or any challenges you encounter as you build your own dimming solutions. Your insights could light the way for others.

Happy dimming!

T. K. Hareendran is a self-taught electronics enthusiast with a strong passion for innovative circuit design and hands-on technology. He develops both experimental and practical electronic projects, documenting and sharing his work to support fellow tinkerers and learners. Beyond the workbench, he dedicates time to technical writing and hardware evaluations to contribute meaningfully to the maker community.

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Infineon Technologies AG claims the industry’s first radiation-hardened (rad-hard) buck controller with an integrated gate drive. The RIC70847 buck controller targets point-of-load power rails in commercial space systems and other extreme environments. Applications include distributed satellite power systems and digital processing payloads, including FPGA and ASIC systems. 
 

(Source: Infineon Technologies AG)

The RIC70847 comprises a 17.1-V buck controller with a 5-V (output) half-bridge gate drive, suited for applications with a power input range of 4.75 V to 15 V and power output range of 0.6 V to 5.25 V. The device meets the MIL spec temperature range of -55°C to 125°C and applications that require a total ionizing dose rating of up to 100 krad (Si) and single event effects characterized up to a linear energy transfer of 81.9 MeV·cm²/mg.

The rad-hard buck controller incorporates load line regulation and fixed-frequency peak current mode control, which is reported to deliver exceptional transient response while reducing the number of output capacitors required. In addition, the high step-down voltage ratios, combined with the 5-V half-bridge gate driver, simplify the design process and minimize component count for a more compact and efficient power management design.

The high level of integration also improves system reliability and reduces the risk of component failure, Infineon said.

The RIC70847 buck controller is housed in a hermetically-sealed 24-lead flatpack or die form, and works seamlessly with logic-level transistors, such as Infineon’s rad-hard R8 power FET. It is available now, along with the RIC70847EVAL1 DC/DC buck controller evaluation board. The eval board features an integrated dynamic load step circuit for transient testing and supports a range of output capacitance and inductor configurations.

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Vishay Intertechnology, Inc. launches a new series of insulated, surface-mount inrush current limiting positive temperature coefficient (PTC) thermistors. The Vishay BCcomponents PTCES series devices offer maximum energy handling up to 340 J with high maximum voltages of 1,200 VDC in a compact package, providing increased board-level efficiency and lower costs in automotive and industrial applications.

Vishay said the new PTCES PTC thermistors offer up to 260% higher energy-handling capabilities compared to competing devices, which helps to reduce component count to save board space and lower overall costs. These devices also offer 20% higher maximum voltages than competing devices.

(Source: Vishay Intertechnology, Inc.)

The PTC thermistors provide current limitation and overload protection in AC/DC and DC/DC converters; DC-Link, energy dump, and emergency discharge circuits; on-board chargers and battery charging equipment; and motor drives. They withstand >100,000 inrush power cycles and are AEC-Q200 qualified for shock and vibration, eliminating the need for reinforced mounting adhesives, Vishay said.

The series is comprised of solder-connected homogeneous ceramic PTCs encapsulated in a UL 94 V-0 compliant, self-extinguishing, washable plastic housing with insulation up to 3 kVAC. The devices feature a low profile of 9.6 mm and can be automatically mounted by pick-and-place equipment to reduce placement costs.

The PTC thermistors are RoHS-compliant and halogen-free. Samples and production quantities are available now, with lead times of 10 weeks. Pricing for U.S. delivery starts at $0.90 each in quantities of 1,000. Click here for the datasheet.

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While compute devices such as CPUs, GPUs, and XPUs are stealing the limelight in the artificial intelligence (AI) era, there is an increasing realization that powering AI at scale demands new power systems and architectures. In other words, data center operators are investing heavily in high-performance computing for AI, but there is no AI without power.

The exponential growth of AI is rapidly outstripping the capacity of the current 54-V data center power infrastructure, driving a transformation toward high-density, reliable, and safe 800-V powered data centers. Here, at this technology crossroads, the new power delivery architecture requires new power conversion solutions and safety mechanisms to prevent potential hazards and costly server downtimes.

Figure 1 AI data center power was a prominent theme at Infineon OctoberTech Silicon Valley 2025. Source: Infineon

At Infineon’s OctoberTech Silicon Valley event held on 16 October 2025 in Mountain View, California, this tectonic shift in data center power infrastructure was a major highlight. The company demonstrated 800-V AI data center power architectures built around silicon, silicon carbide (SiC), and gallium nitride (GaN) technologies.

Infineon has also joined hands with Nvidia to maximize the value of every watt in AI server racks through modular and scalar power architectures. The two companies will work together on data center power aspects, such as hot-swap controller functionality, which enables future server boards to operate in 800-V power architectures. It will facilitate the exchange of server boards on an 800 VDC bus while the entire rack continues operating through controlled pre-charging and discharging of the boards.

At Infineon OctoberTech Silicon Valley, Peter Wawer, division president of green industrial power at Infineon Technologies, spoke with EDN to explain the transition to AI data centers to 800-VDC architectures. He also walked through the demo to show how 800-V power is delivered to AI server racks.

The advent of solid-state circuit breakers

“We are seeing a switch to an 800-VDC architecture in AI data centers, which is a major step forward to establishing powerful AI gigafactories of the future,” Wawer said. “The power consumption of an AI server rack is estimated to increase from around 120 kilowatts to 500 kilowatts, and to 1 megawatt by the end of the decade.”

Inevitably, it calls for higher efficiency and reduced losses as computing power continues to scale at an unprecedented rate. “This evolution brings new challenges,” Wawer acknowledged. “When you want to exchange server boards on an 800-V bus while the entire rack continues operating, you are dealing with substantial power levels.”

For instance, engineers need controlled pre-charging and discharging to avoid dangerous inrush currents and ensure safe maintenance without downtime. While traditional protective devices like fuses and mechanical breakers have served reliably for decades, they were not designed for the ultra-fast fault response required in today’s high-voltage, high-speed environments, where microseconds matter.

That’s where the next generation of solid-state circuit breakers (SSCBs) comes in. The new data center architectural shift is leading to the emergence of SSCBs, which will modernize AI data centers while replacing electromagnetic transformers. SSCBs respond to faults in microseconds with very high precision, which makes power distribution in AI data centers safer, faster, and more efficient.

Figure 2 SSCBs will replace electromagnetic transformers that currently connect the grid to power infrastructure in data centers. Source: Infineon

“To enable these next-generation SSCBs, Infineon introduced the CoolSiC JFET family earlier this year,” Wawer told EDN. “These JFETs offer the ability to combine ultra-low on-resistance—1.5 mΩ at 750 V and 2.3 mΩ at 1200 V—to ensure robust performance even under tough conditions.”

Reliability is another key advantage, he added. “These JFETs are designed to handle sudden voltage spikes and current surges, responding quickly to faults and helping prevent equipment damage or downtime.” Their packaging—aided by top-side cooling and Infineon’s .XT interconnect technology—helps AI data center power systems stay cool and reliable even in the most demanding environments.

These JFETs also reduce the need for external clamping circuits, simplifying system design and enabling more compact and cost-effective solutions. Besides AI data centers, this SSCB technology can help protect electric vehicles (EVs), industrial automation and smart grids, making power distribution safer, more efficient, and ready for the future.

Solid-state transformers, hot-swap controllers, and power modules

At OctoberTech Silicon Valley, Infineon also demonstrated a power system built around high-voltage CoolSiC components for high-voltage DC power distribution to IT racks powered by a solid-state transformer (SST). “The SSTs will be crucial in gigawatt-scale AI datacenters,” Wawer said.

An SST is a power-electronics stack for connecting the grid to data center power distribution. It replaces the conventional systems based on a low-frequency transformer made of copper and steel and an AC-DC converter, enabling a dramatic reduction in size and weight, end-to-end efficiency, and reduced CO2 footprint.

Next, Infineon unveiled a reference board for hot-swap controllers for 400-V and 800-V power architectures in AI data centers. The hot-swap controller functionality is vital to providing the highest levels of protection, maximizing server uptime, and ensuring optimal performance. The REF_XDP701_4800 hot-swap controller reference design is optimized for future 400-V/800-V rack architectures.

Figure 3 Hot-swapping controller designs demonstrated at OctoberTech in Silicon Valley are optimized for 400-V/800-V data center rack architectures. Source: Infineon

Then there were trans-inductance voltage regulator (TLVR) modules specifically designed for high-performance AI data centers. Infineon’s TDM22545T modules combine OptiMOS technology power stages with TLVR inductors to bolster power density, improve electrical and thermal efficiency, and enhance signal quality with reduced transients.

The proprietary inductor design delivers ultra-fast transient response to dynamic load changes from AI workloads without compromising electrical or thermal efficiency. Moreover, the inductance architecture minimizes the number of output capacitors, reducing the overall size of the voltage regulator (VR) and lowering bill-of-materials (BOM) costs.

Figure 4 The TLVR modules deliver benchmark power density and transient response crucial in AI data centers. Source: Infineon

Transition to new power architectures

Jim McGregor, principal analyst at Tirias Research, acknowledges that it’s becoming increasingly challenging to power AI data centers from the grid to the chip level. “It’s critical that power design engineers continuously improve efficiency, power density, and signal integrity of power conversion from the grid to the core.”

Especially when an AI server costs 30 times as much as a traditional server. Furthermore, there is an increasing need to simplify system design, enabling more compact, cost-effective solutions for powering AI data centers.

The imminent shift from the current 54-V data center power infrastructure to a centralized 800-V architecture is part of this design journey in the rapidly evolving world of AI data centers. That inevitably calls for new building blocks—hot-swap controllers, SSCBs, and SSTs—to successfully migrate to new power architectures.

These power-electronics building blocks are now available, which means the transition to 400-V/800-V AI data centers isn’t far off.

Related Content

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• As Data Center Growth Soars, Startup Uses AI to Cut Power Binge

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