ISSUE: February 2021


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» Demystifying Three-Phase PFC Topologies

» A PSU Analytical Power Loss Model For Optimizing The Server Power Delivery Architecture

» Focus On Magnetics:
- Determining Design Power Over An Input Voltage Range (Part 2): Inductor Design Power

» Special Guest Commentary:
GaN Is Revolutionizing Motor Drive Applications

» New Power Products

» Other Top Power News

From the Editor's Desk

David G. Morrison
Editor, HOW2POWER TODAY       

Application trends such as vehicle electrification and adoption of grid-based energy storage are driving the development of higher-power power electronics systems that process tens or hundreds of kilowatts. Over time, such developments will impact all aspects of the electronics ecosystem from components to instruments and design tools, to design and manufacturing services and other areas. In fact, these developments are already underway as evidenced by recent product announcements. However, another aspect of this growth in higher power applications is the increasing need for operation from three-phase power sources and with that, three-phase power factor correction (PFC). An article in this issue by Didier Balocco and Oriol Filló offers a good primer on this subject for designers. They review the motivations for using three-phase power, why PFC is required and discuss the many options and tradeoffs involved in designing a three-phase PFC front end. This article focuses heavily on the various topology options for three-phase PFC, which may suggest to the reader not only that there’s much more to know about these topologies, but also many opportunities for innovation at the device and circuit level. This edition of the newsletter also delves into topics relating to power supply specification. For example, Viktor Vogman presents an analytical power loss model for server power supplies, which supports the optimization of 80Plus PSUs to reduce total cost of ownership for server platforms. In addition, we have a lengthy product roundup on railway power converters. This issue also includes Marco Palma’s commentary on why GaN can be a game changer in low-voltage integrated motors; Dennis Feucht’s part 2 on the design power concept for inductors, the latest power component news and more.


Demystifying Three-Phase PFC Topologies

by Didier Balocco, ON Semiconductor, Vélizy, France and Oriol Filló, ON Semiconductor, Munich, Germany

Three-phase power factor correction (PFC) systems are experiencing a sharp increase in demand with two main drivers propelling this trend. First, there is vehicle electrification. Fast dc electric vehicle (EV) chargers, which are ac-dc conversion systems, require three-phase PFC topologies to efficiently and effectively deliver power above 10 kW. The second driver is the advent of silicon carbide (SiC) power semiconductors, which are are enabling higher power and higher voltage power electronics applications, including three-phase PFC systems. This article introduces the key advantages of three-phase systems and dives into the essential design considerations for these systems. It presents the most common three-phase PFC boost topologies, discusses their pros and cons and provides guidance on how to approach a three-phase PFC design from scratch. Read the article…

Considerations in designing a three-phase
PFC system include unipolar vs bipolar
switching, switching frequency vs. power
devices, modulation scheme (which
relates to the voltages and sectors shown
here), losses and thermal management,
bidirectionality and power flow direction
optimization, and topology.

In the dynamic/peak power
operating mode, even if average
power is kept equal to the max
continuous rating, the actual PSU
efficiency is always lower than the
rated PSU efficiency at the 100%
load point.

A PSU Analytical Power Loss Model For Optimizing The Server Power Delivery Architecture

by Viktor Vogman, Power Conversion Consulting, Olympia, Wash.

Because they reduce data center electricity costs versus less efficient power supplies, 80Plus-certified PSUs have become the market (and industry) standards. But even with the availability of these more-efficient power supplies, there are still opportunities for cost and energy savings. Specifically, the optimization of the sizes and ratings of 80Plus PSUs for the application could further reduce the total cost of ownership for server platforms. Such optimization could be provided very effectively if a PSU power-performance analytical model were available for power architects. This article presents an analytical PSU power loss model that provides a means to assess tradeoffs in continuous vs. peak power ratings of PSUs. This model also can be used for characterizing PSU dynamic efficiency and as a tool for optimization of the system power delivery spec. Read the article…

Sponsored by Payton Planar Magnetics
A monthly column presenting information on power magnetics design, products, or related technology

Determining Design Power Over An Input Voltage Range (Part 2): Inductor Design Power

by Dennis Feucht, Innovatia Laboratories, Cayo, Belize

In part 1, the maximum power handled by the inductor of a PWM-switch converter was defined in relation to input power for the three PWM-switch configurations. The first power term tells us the maximum amount of power the inductor will carry over the input voltage range, but this is not the power rating we can use to optimally design the inductor for size. To that end, we need a new parameter, which the author has dubbed design power. In this part, he defines inductor design power and shows how it varies in each of the PWM-switch configurations. Read the full article…


GaN Is Revolutionizing Motor Drive Applications

by Marco Palma, Efficient Power Conversion, Turin, Italy

In last month’s Safety & Compliance column, “WBG Semiconductors Pose Safety And EMI Challenges In Motor Drive Applications,” Kevin Parmenter made some assertions about the difficulties of using SiC, and to a lesser extent GaN, power semiconductors in large motor-drive applications. This commentary is a response to that article, showing that GaN can be a game changer in low-voltage integrated motors. Read the full article…

Vicor Header

On-Demand Webinar: Tethered UAV Power Matching

Increasing the capabilities of a UAV can put significant pressure on its power source and lead to tether power loss. These tether losses can be minimized by increasing the size of the wire, but a limit is soon reached. A better approach is to match the Ground Based Source “GBS” architecture with a power converter in the aircraft. Watch this 15 minute webinar to see how Vicor solved this challenge for a customer.

Watch the webinar!

More from Vicor:

World’s first commercialized hydrogen fuel cell power pack for UAVs

Boeing satellites use radiation-tolerant power modules from Vicor

Attributes of high performance power module packaging



Power Product Roundup

Railway Power Converters Reach For Wider Input Range And Other Improvements

by David G. Morrison, Editor,

This article offers a roundup of news about railway-grade power converters introduced over approximately the past two years. It mainly covers dc-dc converters at power ranges from 10 W up to 300 W for input voltages from about 9 V up to 176 V, which covers a variety of popular bus voltages. This article also includes a few converters designed for operation from a high voltage bus of 750 V or 900 V nominal. Additionally, this roundup highlights some recently introduced ac-dc power supplies, mostly in the 150-W to 300-W range, plus one 3-kW unit. Other products discussed include USB chargers and sine wave inverters. Read the full story…

Among the latest dc-dc converters for railway applications,
"ultra-wide" input voltage range is often cited as a
product differentiator. High power density, high efficiency
and wide temperature range are other touted features.

Rohm Semiconductor’s 4G SiC

Next-Gen SiC MOSFETs Are Optimized For xEVs And Industrial Applications

 Graphs: A comparison of Rohm’s fourth-generation 1200-V SiC MOSFETs with the company’s existing third-generation n-channel devices reveals a 40% reduction in RDS(ON).

 Graphs: In the 4G parts, the energy required to switch the devices on and off has been significantly reduced and reverse-recovery energy has been slashed, leading to dramatic reductions in total switching loss.

See the full story…

Picotest’s P2102A two-port
“browser” probe.

Two-Port Probe Revamps Impedance Measurement For PI And PDN Applications

 Photo: The PDN probe enables PDN low and ultra-low impedance measurements for power integrity applications. In the past, performing PDN impedance measurement required soldering of coax or preparing the PCB with RF connectors. But this “browser” probe can easily and quickly be moved from point-to-point/rail-to-rail simply by reseating the probe points. It can measure submilliohm power rail impedances up to bandwidths of 300 MHz.

See the full story…

Renesas Electronics’ P9418 60-W
wireless power receiver IC.

Receiver IC Puts Wireless Charging Speeds On Par With 60-W Adapters

 Diagram: This wireless power transmitter/receiver IC delivers up to 60 W as a receiver, enabling faster wireless charging for smartphones, laptops and notebook devices in a high density solution. In the WattShare mode, the chip can transmit up to 10 W for wireless charging of other devices.

See the full story…

Teledyne LeCroy’s HVD3220
high-voltage differential probe.

High-Voltage Probe Measures SiC- And GaN-Based Power Converters

 Photo: A 2-kV, 400-MHz high-voltage differential probe is well suited for measuring GaN- and SiC-based power conversion system outputs, line outputs, in-circuit device switching outputs, and voltages across other components.

See the full story…

More Power Products. . .

24-V Dual-Channel Gate Driver For Large Power Switches

A Versatile Platform To Evaluate GaN Drivers And Transistors

80-V Resistor-Equipped Transistors Save Space In 48-V Applications

Fast Recovery AEC-Q Rectifiers Offer High Performance


The JEDEC Solid State Technology Association has published the JEP183: Guidelines for Measuring the Threshold Voltage (VT) of SiC MOSFETs, the first publication by JEDEC’s JC-70.2 SiC subcommittee.

The IEEE Nuclear and Space Radiation Effects Conference (NSREC 2021), which is scheduled for July 19-23, 2021, has extended the abstract deadline to February 26, 2021.

The PCIM Europe exhibition and conference originally planned for May 4 – 6, 2021 has been rescheduled to August 31 - September 2, 2021. The venue remains the Nuremberg Exhibition Centre but the live event will be complemented by a digital format.

Coordinated by Infineon Technologies, the Europe-wide research initiative Intelligent Reliability 4.0 (iRel40) aims to improve the reliability of electronic systems and microelectronic components.

ROHM has completed construction of an environmentally friendly building to expand production capacity of SiC power devices.

On March 10, 2021 at 10 am PDT, Ray Ridley will host a free 2-hour online masterclass on frequency response measurements for power systems.