ISSUE: March 2020


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» Current Drive Can Overcome Pitfalls Of Class D Audio Amplifiers

» Determining Whether A Film Capacitor Can Handle One AC Voltage Imposed On Another

» Focus On Magnetics:
How To Choose Magnetics Materials—Beyond Ferrites And Iron-Powder

» Spotlight On Safety & Compliance:
PFC (Part 2): How Current Harmonics Cause Distortion And The Role of the Delta-Wye Transformer

» New Power Products

» Industry Events:
- Power Semiconductors Abound AT CES 2020
- PCIM Europe 2020 Conference Program Features More Than 300 Contributions
- International 3D-PEIM Symposium Postponed Until June 2021

» Other Top Power News

From the Editor's Desk

David G. Morrison
Editor, HOW2POWER TODAY       

This year’s APEC conference, which was to be held next week in New Orleans, has fallen victim to concerns about the COVID-19 virus and has been cancelled—more or less at the 11th hour. For the many who would have attended, this is a lost opportunity to present and learn about the latest R&D and trends in power electronics, to see the latest power products, take tutorials, catch up with colleagues and start dialogues with others in the field. While an online version of the conference is being planned as a make-up, there’s no substitute for the in-person communications that such live events foster. Hopefully, the health crisis will abate sooner rather than later and we’ll be able to return to participating in similar professional meetings. One aspect of APEC that will be missed this year is its presentation of the latest power semiconductor developments, which have helped us to gauge the progress of wide-bandgap technology. While there’s no direct substitute for that experience, a number of power component developments and announcements that would have been seen at APEC were previewed at this year’s CES. So please check out our coverage of that product news in our feature “Power Semiconductors Abound AT CES 2020”. This issue also presents the usual technical discussions with articles describing a design alternative to Class D audio amps, how to assess film capacitor suitability when one ac voltage is superimposed on another, how to select magnetics materials for an SMPS design given the full range of material options, part 2 of our PFC discussion and more.


Current Drive Can Overcome Pitfalls Of Class D Audio Amplifiers

by Anthony Esposito, Avatar Engineering, Fountain Hills, Ariz.

My background includes over a decade in the design of medical MRI digital gradient amplifiers. In many ways, MRI gradient amplifiers perform similarly to class D audio amplifiers except that the high power and absolute accuracy is well beyond what commercial audio amplifiers can achieve. In the MRI, the drive employs a controlled current to create an accurate magnetic field gradient across the patient without direct feedback of the magnetic field. The driven gradient coils are complex loads and are typically modeled as third- or fifth-order impedances. Driving these complex impedances with a controlled current rather than voltage, results in greater accuracy. The same benefit can be obtained when driving a loudspeaker with a current and this approach also eliminates many of the errors associated with using class D amplifiers to drive speakers. It can also override the need to migrate from silicon to GaN power transistors in these amplifiers. Read the article…

Utilizing a current-sensing method
improves accuracy between the drive
signal and current supplied to the voice
coil that provides the force to the
speaker cone.

Lifetime expectancy for a film
capacitor is a function of the ratio of
the applied operating voltage to the
rated voltage, and the ambient

Determining Whether A Film Capacitor Can Handle One AC Voltage Imposed On Another

by Samuel Accardo, KEMET, Boston, Mass.

Customers reach out to KEMET on a daily basis to help them determine whether or not a particular capacitor series or an individual part number will work in their circuit. More often than not, answering the question requires us to learn a little about the circuit and the type of environment in which the capacitor is expected to operate. A recent, but common type of question is along these lines, “Can I use a C44BXFP4100ZB0J, C44BXFP4150ZA0J or C44BXGP4200ZA0J with a 60-Hz 720-Vrms ac voltage imposed on 10% 16-kHz pk-pk ripple?” To determine whether a capacitor can handle two applied ac voltages, we need to know more about the operating conditions in the application and its life expectancy as will be explained in this article. Read the article…

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

How To Choose Magnetics Materials—Beyond Ferrites And Iron-Powder

by Dennis Feucht, Innovatia Laboratories, Cayo, Belize

The simple and well known rule in designing transformers and coupled inductors is ferrites for transformers; iron-powder for inductors. While following this rule of thumb gives designers a starting point in selecting a core material, it does not enable the designer to choose the optimal core material within the ferrite and Fe-pwd classes of materials. Nor does it allow them to take advantage of the other core materials whose properties fall between those of Fe-pwd and ferrites. Depending on circuit operating conditions, it may be another core material such as NiFe, FeSiAl or NiFeMo that offers optimal performance in the application. Or a gapped ferrite may be best. This article describes the use of ripple factors to achieve optimal selection of core materials among the various ferrite, iron-powder and other core material options. Read the full article…

The range of current ripple factor γc
for core materials commonly used in
switched-mode power converters. When
the circuit γ matches γc, the core
transfer energy is maximized.

Sponsored by Power Integrations
A monthly column discussing standards and regulatory requirements affecting power electronics

PFC (Part 2): How Current Harmonics Cause Distortion And The Role of the Delta-Wye Transformer

by Kevin Parmenter, Chair, and James Spangler, Co-chair, PSMA Safety and Compliance Committee

The first part of this article reviewed the evolution of power factor correction (PFC) requirements and discussed the IEC 61000-3-2 PFC standard. Here in part 2, the relationship between line frequency harmonics and distortion is analyzed, and we explain how the delta-wye transformer corrects this distortion on the power grid. Read the full article…


NAWA Technologies’ NAWACap POWER

Novel Carbon Nanotube Technology Creates More Powerful Ultracaps

 Graph: NAWA’s ultra-fast carbon electrodes enable a new generation of high-power supercapacitors (NAWACap Power) with ESR that is said to be more than 10 times lower than the competition and power densities said to be between 10 and 100 times higher than existing supercapacitors.

See the full story…

Power Integrations’ 1SP0351

Plug-And-Play Gate Drivers Suit 4500-V Press-Pack IGBT Modules

 Photo: The single-channel plug-and-play gate drivers are optimized for operation of 4500-V Press-Pack IGBT power modules from manufacturers such as Toshiba, Westcode and ABB. The drivers are well suited for high-rel applications such as HVDC voltage-source converters, STATCOM/FACTS and medium-voltage drives.

 Drawing: The gate driver is based on the SCALE-2 chipset, which uses sophisticated digital control techniques to reduce component count versus conventional solutions.

See the full story…

Texas Instruments’ TPS546D24A
40-A buck converter.

40-A Buck Converter IC Is Stackable Up to 160 A

 Diagram: A member of TI’s SWIFT family, this highly integrated, PMBus-compatible point-of-load converter is capable of high-frequency operation and 40-A current output from a 7-mm × 5-mm QFN package. Two, three, and four devices can be interconnected to provide up to 160 A on a single output.

See the full story…

Efficient Power Conversion’s
EPC9144 laser diode driver
demo board.

Time-Of-Flight Demo Board Showcases GaN Speed In Driving Lasers

 Photo: The development board is intended to drive laser diodes with high current pulses with total pulse widths as short as 1.2 ns and currents of up to 28 A, highlighting the fast switching speed of the automotive-qualified 15-V EPC2216 eGaN FET. The pulses produced by the eGaN FET drive laser diodes, VCSELs or LEDs up to ten times faster than an equivalent silicon MOSFET.

See the full story…

More Power Products. . .

System Combines Multiple Instruments And Software For Designing And Measuring Power Systems

Capacitor Simulation Tool Characterizes New High-Rel MLCCs


Power Semiconductors Abound AT CES 2020*

by David G. Morrison, Editor,

When you think of the CES show, your first thought may not be of MOSFETs, IGBTs, power ICs and modules. But this massive tech show has become a showcase for many of the latest SiC, GaN and silicon power components—and not just for consumer applications. In their meeting rooms and suites at CES 2020, power semiconductor manufacturers displayed the latest application examples—both reference designs and actual customer products—using their semiconductor devices. In this article I discuss the power components and demos shown at CES 2020 by the likes of ST, ON, Infineon, Rohm and others. Read on to learn about some of the newest discrete power semiconductors, power modules, voltage regulators and specialized power management ICs (PMICs) and the applications that inspired them. For those interested in wide-bandgap technology, this feature offers some previews of SiC and GaN devices currently in development including plans for the first GaN products from some established chip makers.

Read the full story…

*This article is a follow-up to my initial coverage of CES2020 where I reported
on trends and developments seen in the main exhibition halls.

PCIM Europe 2020 Conference Program Features More Than 300 Contributions

Running in parallel to the extensive exhibition, the PCIM Europe conference, which will be held from May 5 – 7, 2020 in Nuremberg, will offer a multifaceted program consisting of lecture and poster presentations, keynotes, special sessions and exclusive seminars and tutorials. Current research is focused on the applications of wide-bandgap technologies at component and chip level, in packaging and interconnection technologies and packaging design. Technical advances in silicon carbide (SiC) and gallium nitride (GaN) devices have also made it possible to create power electronic converters and evaluate the tremendous advantages of using them in systems.

Read the full story…

International 3D-PEIM Symposium Postponed Until June 2021

The International 3D Power Electronics Integration and Manufacturing (3D-PEIM) Symposium, which was initially planned for June 2020 at Osaka University, Japan has been postponed due to the Coronavirus threat until June 21-23, 2021 at Osaka University.

Read the full story…


STMicroelectronics has agreed to acquire a majority stake in French GaN innovator Exagan. Exagan’s expertise in epitaxy, product development and application know-how will broaden and accelerate ST’s power GaN roadmap.

NAWA Technologies has successfully completed its second round of funding with new investors. The fund raising will be used for investment in manufacturing of NAWA’s technology and winning customer orders, which includes installation of a first-of-its-kind ultracapacitor production line.

Organizers have cancelled the Components for Military and Space Electronics (CMSE) Conference & Exhibition, which was scheduled for April 21-23, 2020 in Los Angeles, but are considering hosting a virtual conference instead.