ISSUE: May 2018


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» Dual Buck Doubles The Duty Cycle For Ultra Low-Voltage Applications

» Analyzing The Effect of Voltage Drops On The DC Transfer Function Of The Buck Converter

» Achieve Precise High Current Monitoring Using Standard Surface-Mount Resistors

» Focus On Magnetics:
Magnetic-Electric Analogs Relate Magnetic Fields To Familiar Circuit Quantities

» Spotlight On Safety & Compliance:
Beware The Pitfalls Of Power Suppy Hipot

» Book Review:
Introduction To Electric Vehicle Engineering Explains History And Design Concepts

» Spotlight On Education & Research:
PowerAmerica: Accelerating The Next Generation Of Wide-Bandgap Power Electronics

» New Power Products

» What's New at HOW2POWER.COM

» Other Top Power News

From the Editor's Desk

David G. Morrison
Editor, HOW2POWER TODAY       

Collaborations between industry and academia help to propel new technologies forward. There are many examples of this in power electronics with universities having their own industry consortia to support their research programs. Then there are organizations working at a higher level to advance technology by supporting and coordinating the efforts of many companies and research institutions. PowerAmerica is one such group. This consortium of almost 50 organizations from industry and academia is working to speed up acceptance of SiC and GaN power devices in the marketplace. You can read about the R&D projects they have funded and the educational and training programs they offer in this month’s Spotlight on Education and Research. In the past when silicon power MOSFETs and IGBTs arrived on the market, we didn’t have organizations like Power America working behind the scenes to help move the technologies to market. But then, the pressure to do so was probably not as great then. Though he’s not writing about SiC and GaN, the title of Ken Coffman’s new Power Integrity Insights article sums up the urgency that motivates collaboration today: “The Relentless Progression Of Power Supply Requirements.” While new components are one means to try and keep pace with power supply demands, creative approaches to circuit design and analysis offer other means of achieving better performing power supplies as demonstrated in the various other articles in this issue.


Dual Buck Doubles The Duty Cycle For Ultra Low-Voltage Applications

by Patrice Lethellier, It Can Be Done, Salt Lake City, Utah

The large microprocessors (Intel, Sun, IBM) require a high current and a low voltage. A core voltage of 0.6 V at 200 A is not uncommon. It can be an even lower voltage in sleep mode. Typically the topology used to supply this voltage is a multiphase buck with 8 to 12 phases. The input voltage is 12 V and in this example where the output voltage is 0.6 V, the buck has to work at a duty cycle close to 5%. The duty cycle gets even lower in sleep mode where the output voltage can be 0.3 V. At a duty cycle below 5%, the on-time barely exists and efficiency is very low. This article presents an alternative multiphase buck topology that performs the same voltage transformation as the conventional multi-phase buck but without some of the drawbacks. Read the full story…

This topology consists of two bucks ganged
with paralleled and sequenced outputs.

During the switch on-time, current circulates
through the MOSFET and other ohmic paths.
The associated voltage drops can have an
impact on the dc transfer function of the buck.

Analyzing The Effect of Voltage Drops On The DC Transfer Function Of The Buck Converter

by Christophe Basso, ON Semiconductor, Toulouse, France

Switching converters combine passive elements such as resistors, inductors, capacitors but also active devices like power switches. When you study a power converter most of these components are considered ideal: when switches close they do not drop voltage across their terminals, inductors do not feature ohmic losses and so on. In reality, all these elements, either passive or active, are far from being perfect. In this article, we will study their effects on the dc transfer function of a buck converter. We will also apply this analysis to a forward converter, which is a buck-derived topology. Read the full story…

Achieve Precise High Current Monitoring Using Standard Surface-Mount Resistors

by Viktor Vogman, Power Conversion Consulting, Olympia, Washington

In low-voltage, high-current applications, in which sensor voltage drop may noticeably impact power distribution efficiency, designers are required to use very low (sub-milliohm) resistance sensors for current sensing. High-power-rated sub-milliohm sensors often come with Kelvin connect terminals, which simplify their layout, but take up more PCB space, and are less accurate and more expensive than standard precision surface-mount (SM) parts. Designers generally prefer to select standard SM resistors. When connected in parallel, conventional SM two-terminal parts can support the sub-milliohm resistance range of the sensor. With proper PCB trace routing and summing signals of paralleled sensors a much better (1%) current signal monitoring accuracy can be achieved even without calibration. Read the full story…

With unequal current path lengths for
each of the paralleled resistors single
Kelvin pair sensing accuracy will be
impacted by trace resistance and this
error needs to be taken into account

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

Magnetic-Electric Analogs Relate Magnetic Fields To Familiar Circuit Quantities

by Dennis Feucht, Innovatia Laboratories, Cayo, Belize

Circuit designers are usually able to think more easily about the circuit behavior of capacitors than inductors. Inductance is the dual of capacitance; exchange v and i in capacitor equations and they apply to inductors. This dualism can be extended to circuit laws too, and the three most basic laws of circuits (Ohm’s Law, KVL and KCL) have magnetic counterparts. In this article, the author derives these equivalents and examines them. Finally, he explains how the magnetic counterparts to circuit laws can be applied in transformer design. Read the full story…

How2Power’s Simulation Survey       

For a chance to win a free technical e-book
of your choosing from CRC Press*, take this short 5-question
survey on power supply simulation from HOW2POWER.

(E-book options include titles on this CRC Press list. Choices are limited to e-books valued up to $160. Multi-volume sets are not included.
10 winners will be selected. Drawing to be held in July 2018.)

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

Beware The Pitfalls Of Power Suppy Hipot

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

What is hipot (high potential) testing and what is it for? A dielectric withstanding voltage test is used to determine the ability of equipment with an installed power supply to protect against electrical shock. The dielectric withstand voltage test is typically referred to as a hipot test and involves applying a specified high voltage between the points being tested and measuring the resultant leakage current. The test has been with us a long time. However, as power supplies have developed and EMC requirements have become more stringent in, for example IEC 60601 4th edition EMC, we have seen customers needing more guidance in the proper application of the testing. Moreover, it should be emphasized that for switching power supplies, the hipot test should be considered a destructive test. What is meant by this?. Read the full story…


Introduction To Electric Vehicle Engineering Explains History And Design Concepts

Modern Electric, Hybrid Electric, and Fuel Cell Vehicles,Third Edition, Mehrdad Ehsani, Yimin Gao, Stefano Longo Kambiz Ebrahimi, CRC Press Taylor & Francis Group, 2018, 546 pages, glossy hardback, ISBN-13: 978-1-4987-6177-2.

Reviewed by Dennis Feucht, Innovatia Laboratories, Cayo, Belize

This book surveys the technology of land-based vehicles with electric propulsion. Two of the authors are electrical and electronics engineering professors and the other two are in mechanical engineering. Whether this book belongs in the power electronics section of the library (under batteries or electrochemistry) or in the automotive engineering section required some consideration that landed it in the automotive section of my library. The book contains a large amount of mechanical engineering, though all of it is related to electric or hybrid vehicle drive trains (propulsion). Read the full story…


PowerAmerica: Accelerating The Next Generation Of Wide-Bandgap Power Electronics

by Julia Casadonte, Communications Manager, PowerAmerica, Raleigh, N.C.

Power electronics systems based on silicon carbide (SiC) and gallium nitride (GaN) semiconductors are becoming mainstream. Supporting the transition to these long-anticipated technologies is PowerAmerica, a consortium of nearly 50 industry and university members focused on accelerating the adoption of SiC and GaN technology in a wide range of power electronics systems. Based at North Carolina State University, members range from startups to multinational corporations, as well as top research universities across the U.S. Since its inception in January 2015, PowerAmerica has awarded funding of approximately $44 million (excluding 1:1 cost matching) for 59 SiC and GaN projects in the areas of large volume power device fabrication, module development, device reliability, and power electronic applications—all boosting manufacturing in the United States. Funding for these projects is provided by the U.S. Department of Energy, the state of North Carolina, industry, and academia. Read the full story…

A collaboration between John Deere
and the DoE’s National Renewable
Energy Laboratory developed
this high-power SiC traction
inverter to electrify heavy-duty
construction vehicles.


ROHM Semiconductor‘s
BD372xx series linear regulators.

Power Supply ICs Are Honed For High-Fidelity Audio

 Diagrams: These linear regulators are said to be the first audio power supply ICs that excel in all three characteristics critical to audio performance— voltage stability, noise level, and power supply symmetry. The company’s proprietary analog power supply design technology leverages power processes with audio quality expertise.

More details…

Renesas Electronics’ ISL91302B,
ISL91301A and ISL91301B
power management ICs.

PMICs Boast Better Efficiency And Solution Size For Powering Processors

 Diagram: The ISL91302B delivers up to 20 A and 94% peak efficiency in a 70-mm2 solution size for application processors, AI processors, industrial MPUs, and FPGAs. This model is available in a dual-phase (2 + 2) configuration supporting 10 A from each output, a triple-phase (3 + 1) configuration supporting 15 A from one output and 5 A from the second output and a quad-phase (4 + 0) configuration supporting 20 A from one output.

 Diagram: The ‘301A triple-output PMIC and the ‘301B quad-output PMIC both deliver up to 16 A with 94% peak efficiency.

More details…

ABSOPULSE Electronics’
CTP 1000-F7W sine wave inverters.

SiC-Based Sine Wave Inverters Deliver 1 kVA In A 400-in.3 Package

 Photo: These sine wave inverters use silicon carbide semiconductors to achieve 90% efficiency at full load in a significantly smaller package size than previous three-phase 1-kVA inverters. Units measure 11 x 2.6 x 14 in.

More details…

Teledyne LeCroy’s WavePro
HD high-definition oscilloscopes.

HD Oscilloscopes Deliver 12-bit Resolution, 8-GHz Bandwidth And Up To 5 Gpts Of Memory

 Drawing: At the heart of these oscilloscopes is a new 8-GHz chipset comprising a low-noise front-end amplifier and a 12-bit ADC. That chipset, tightly integrated with a new low-noise, high-bandwidth system architecture, unlocks the full potential of HD4096 High Definition Technology in an 8-GHz, 12-bit scope. Their high bandwidth and high vertical resolution are well suited for measurement and analysis of on-die and system PDN behavior.

More details…

Kinetic Technologies’ KTU1101
USB type-C port protector..

USB Type-C Data Line Protection IC Responds To Overvoltages In 15 ns

 Diagram: The port protector provides ESD, surge and overvoltage protection for USB type-C CC/VCONN and SBU signal lines. According to the company, its OVP response time is significantly better than competing solutions.

More details…


• 400-V Linear Regulators Deliver Constant LED Current In Compact Packages     More details…

• “Deep Sleep” Load Switch Prevents Battery Discharge During Product Shipment    More details…


Power Integrity Insights: In "The Relentless Progression Of Power Supply Requirements," Renesas’s Ken Coffman discusses, some of the critical challenges facing power supply designers today and why controlled impedance is the best tool for dealing with power supply requirements in real-world applications. Read the article…

HOW2POWER's Battery Related Conferences and Trade Shows list is now updated for 2018. Browse this popular list to learn where the latest battery R&D is being presented.

All New: HOW2POWER's Medical Related Conference list--useful for anyone developing power products for medical applications. Browse the list…

Find this and more on HOW2POWER.COM.


Both the technical program and the 2018 conference brochure for NSREC (the IEEE Nuclear and Space Radiation Effects Conference) are now available online. In addition, for companies interested in participating in the exhibition, the exhibits are now open.

The IEEE Industrial Applications Society and the IEEE Power Electronics Society are offering 30 student travel grants of $500 each to attend ECCE 2018.

LTEC, in collaboration with Anagenesis, has released a market research report on advanced power packaging technologies, “Power Supply in a Package (PSiP) and Power Supply on Chip (PwrSoC)—The Power Density Challenge Continues.” For more details, see the brochure.

CPES has announced that proceedings and photos from its 2018 Annual Conference are available online.

According to a report from IHS Markit, the global battery energy storage pipeline grew to 10.4 GW at the end of the first quarter of 2018.