ISSUE: August 2017


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» Circumventing Loss In An RC Circuit Leads To More Efficient Power Converters

» Receiver Chip Implements Efficient, Flexible Wireless Charging For Wearables

» A Guide To Selecting Industrial Battery Chargers For Material Handling Applications

» Focus On Magnetics:
Ferrite Core Magnetics (Part 2): Gapped Ferrite Cores

» Special Guest Commentary:
Global IP, Invention, Innovation And Benefit: What Would Thomas Jefferson Say?

» New Power Products

» Industry Events:
Test Drive The Latest Design Tools And Components For Power Electronics And Electric Machines At ECCE 2017 Expo
and More Power News From NSREC 2017

» Other Top Power News

» Kudos2

From the Editor's Desk

David G. Morrison
Editor, HOW2POWER TODAY       

At this time of year, your thoughts may be drifting more to vacations and barbecues rather than technical topics. But even if you’re not focused on work at the moment, I hope you’ll “get a charge” out of the articles in this issue as our three design features all relate somehow to the charging theme. In our top design feature, authors from the University of Waikato and Auckland University of Technology explore innovations in power converters that stem from exploiting certain characteristics of the simple RC circuit and the long time constants associated with charging of supercapacitors. Meanwhile, a feature from engineers at Maxim Integrated highlights the benefits of a receiver chip for wireless charging of wearables, including peer to peer charging. Finally, we have an article from Ametek that reviews the basics of industrial battery chargers for material handling and the criteria for selecting them. This issue also brings you our Focus on Magnetics column—a continuation of Dennis Feucht’s series on ferrite magnetics looking at gapped cores. Shifting gears from the more technical articles, we present a thought-provoking commentary on the disparities in treatment of IP rights in different countries. On the product front, we have a power supply roundup that will help bring you up to speed on power supplies for railroad applications, more rad hard power news from NSREC, a preview of the upcoming ECCE 2017 expo and more.


Circumventing Loss In An RC Circuit Leads To More Efficient Power Converters

by Nihal Kularatna, University of Waikato, Hamilton, New Zealand; Kosala Gunawardane, Auckland University of Technology, Auckland, New Zealand; and Thilanga Ariyarathna, University of Waikato, Hamilton, New Zealand.

The charging of a capacitor in a simple RC loop incurs losses in the resistive portion of the circuit. However, the efficiency of the charging circuit varies widely with the initial voltage on the capacitor at the start of charging. If the capacitor in question is a supercapacitor, which results in long time constants, we can take advantage of this relationship between circuit efficiency and capacitor voltage to create novel ac-dc converters with improved efficiency. This article describes two novel ways in which the RC circuit can be combined with power converters to negate the resistive loss of the RC circuit. One approach replaces the resistive part of the circuit with a useful resistance such as a loaded dc-dc converter or voltage regulator. The other approach places a supercapacitor ahead of a linear voltage regulator as a lossless voltage dropper. Read the full story…

Novel power converters exploit the principle
that in a simple RC circuit, the capacitor
charging efficiency will vary with the
source voltage as well as the
pre-charge voltage of the capacitor.

Use of an active bridge rectifier
with low-on-resistance MOSFETs
reduces losses versus a
standard diode bridge.

Receiver Chip Implements Efficient, Flexible Wireless Charging For Wearables

by Scott Kim, Nazzareno (Reno) Rossetti, Raymond Park, Maxim Integrated, San Jose, Calif.

Wireless charging is the next big wave in portable electronics. But the field is still young, with competing technologies and no definitive standard. Like other critical blocks for portable gadgets, the wireless power receiver must utilize minimal space while operating on a single charge for a long time. Accordingly, the receiver must be very small, highly efficient, and compliant with multiple standards. This article discusses the challenges of designing an inductive charging wireless power receiver in today’s climate and introduces an innovative wireless charging solution based on the MAX77950 wireless power receiver IC. This device incorporates features that improve efficiency while accommodating both WPC and PMA protocols. The IC also enables wireless power transfer to a peer device. Read the full story…

A Guide To Selecting Industrial Battery Chargers For Material Handling Applications

by Jeff Harrison, AMETEK Prestolite Power, Troy, Ohio

Specifiers of industrial battery chargers need to understand how the requirements of their particular application influence the choice of charger type. This article outlines the key considerations including what questions need to be asked, and describes at a high level the differences between the three major charger technologies—ferroresonant, high-frequency and SCR. In addition to providing an overview of the internal power supply technology found within these chargers, this article also calls out some of the typical charger specifications. Furthermore, it introduces the concept of opportunity charging. While this article is aimed primarily at specifiers of industrial battery chargers, it may also be useful to novice designers of these chargers. Read the full story…

A ferroresonant charger maximizes
battery life with its constantly tapering
charge that is automatically regulated
by the “on charge” battery voltage.

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

Ferrite Core Magnetics (Part 2): Gapped Ferrite Cores

by Dennis Feucht, Innovatia Laboratories, Cayo, Belize

Gapped ferrite cores are used to store transfer energy, as are iron powder cores. Yet they differ in important ways. This article describes how the differences affect the design of inductors, transformers and coupled inductors, and how transfer power is maximized for high-ripple cores. Transformer optimization results from part 1 are also derived from the standpoint of large-ripple design. We begin by explaining how calculation of the operating point H differs for ferrite gapped cores versus powder cores, and how to find the operating point and the saturation limited turns for gapped ferrite cores. Read the full story…


Global IP, Invention, Innovation And Benefit: What Would Thomas Jefferson Say?

By At Will, Electronics Engineer

It seems that big data has invaded every aspect of everything. My 10x oscilloscope probe has an ROI associated with it and should it not meet or exceed that metric, it is discarded by a cadre of “blackbelts” in this or that fashionable trend armed with tablet computers and urgency. Try taking measurements without it—but that’s not the point or the theme of the transitory invasion. This is all done in the name of continuous improvement with the end goal of austerity. Save more, make more and Wall Street goes wild. So how then does this tie to IP and matters patentable? The underlying, controlling question that needs to be asked is how all of this austerity and lean operation ties to matters of law. In this guest commentary, the author looks at disparities in how patents are treated and how innovation is rewarded in the U.S. and abroad, and the implications for engineers and the global companies that employ them. Read the full story…

Vicor Logo


The Benefits of Efficiently Wrapping Power Systems

Whether your design has strict space constraints or not, smaller systems are usually more attractive to customers. This blog post discusses how you can use power components to incorporate the power system into the mechanical design. “Wrapping” your enclosure around the power architecture creates a more integrated and higher performance system, and saves space.

Read this article

More from Vicor:

White Paper Explains How to Meet Power Demands of Modern Automotive Systems

Download Vicor’s EMI Checklist for Power System Designers

384VDC to 24VDC Isolated Voltage Transformation with Power Density of 2400W/in3



Texas Instruments’ three-phase,
GaN-based inverter reference design.

GaN-Based Inverter Reference Design Raises Performance For AC Servo Drives

 Photo: The inverter reference design helps engineers build 200-V, 2-kW ac servo motor drives and industrial robotics.

 Graph: TI’s LMG3410 600-V, 12-A GaN power module enables the inverter to switch up to 5x faster than silicon FETs, while achieving efficiency greater than 98% at 100 kHz and >99% at a 24-kHz PWM frequency.

More details…

Artesyn Embedded Technologies’AVE450,
AVE500 and ADH700 dc-dc converters.

50-V Halfbrick Converters Enable GaN Wireless Power Amps

 Photo: Three series of 50-V dc-dc converter modules support the growing number of wireless base station and remote radio head deployments using GaN and high-voltage LDMOS technology for increased power density and higher efficiency.

More details…

Infineon Technologies’
EconoPIM 3 IGBT modules.

150-A IGBT Modules Boost Power Density

 Photo: Targeting motor controls for drives in elevators, escalators, fans or pumps. IGBT modules in the EconoPIM 3 package offer a 150-A current rating in a footprint that previously was limited to 100 A. Each module contains a three-phase rectifier, brake chopper, three-phase inverter and NTC thermistor.

More details…


• PMICs Increase Battery Life In “Hearables”  More details…

• 1000-V Input Industrial DC-DC Converters Deliver 500 W    More details…

• Smart Gate Driver Photocoupler Features Improved Desaturation Sensing    More details…


Power Supplies Keep Railway Systems On Track

by Spencer Chin, Contributing Writer

Driven by the need to provide more reliable power for next-generation railway systems, power supply manufacturers have introduced a slew of products especially designed to meet the power specifications and operating conditions of railway power converters and subsystems. Railway power supplies must be built to withstand the harsh shock and vibration prevalent in railroad equipment, as well as be able to withstand high surge currents, transient voltages, and EMI. This Power Product Roundup on railway power supplies primarily highlights dc-dc converters though some models also offer battery charger or ac-input versions. The power converters featured in this article were introduced over the past 12+ months.

More details…


Test Drive The Latest Design Tools And Components For Power Electronics And Electric Machines At ECCE 2017 Expo

by David G. Morrison, Editor,

Now in its ninth year, the Energy Conversion Congress and Expo (ECCE 2017) continues to grow as a unique forum for presenting the latest developments in electrical and electromechanical energy conversion. This year’s event will be held October 1-5 at the Duke Energy Convention Center in Cincinnati, Ohio. Essentially, this is a conference devoted to power electronics and electric machines (mainly motors) with a focus on the higher-power applications where energy consumption is significant and its impact on society comes under increasing scrutiny. When not in the technical sessions learning about the latest R&D, attendees have opportunities to discover the latest commercial products and tools for designing power electronics and machines in the ECCE Expo. This article offers a sampling of the products that will be on display there. Read the full story…

Scenes from last year’s ECCE expo.

More Power News From NSREC 2017

by David G. Morrison, Editor,

Last month we previewed some of the power components that vendors planned to display at the IEEE Nuclear and Space Radiation Effects Conference (NSREC 2017) being held July 17-21. In this post-conference follow-up, we present details on additional components that were demo’d and displayed in NSREC’s industrial exhibition. Read on for more news about rad hard buck converter ICs and modules addressing a range of power levels and varying requirements for radiation immunity. There’s also news about power MOSFETs & SSRs, optocouplers, and for possibly the first time, rad hard power sequencing ICs. Read the full story…


ARPA-E’s PNDIODES (Power Nitride Doping Innovation Offers Devices Enabling SWITCHES) program seeks to develop transformational advances in the process of selective area doping in the wide-bandgap semiconductor, gallium nitride, and its alloys. Click here to read about the companies and projects being funded.

Vicor has released the results of a survey it recently conducted among professional power engineers, identifying and ranking engineers' most frequent challenges when designing new power systems. For survey results, see the whitepaper.

Power Integrations, a provider of high-efficiency, high-reliability ICs for ac-dc, LED lighting and gate driver applications, has announced a worldwide distribution agreement with Future Electronics.

The Power Electronics Industry Collaborative (PEIC), has elected Nanci Vogtli of Concrete Logic to its board of directors. Concrete Logic is a technology consulting firm specializing in the cleantech hardware industry.

Helix Semiconductors is now sampling its eMpower HS100 chipset, which uses capacitive-based voltage reduction to convert ac power to 5 Vdc with more than 90% end-to-end efficiency from a full load of 10 W all the way down to 100 mA.


Infineon for being honored with a “Supplier of the Year Award” from Japanese automotive system supplier DENSO. 

Anecto for winning the Testing Laboratory of the Year award at the Irish Lab Awards 2017. The Galway, Ireland-based ISO 17025 accredited laboratory tests electronics-based products for medical equipment, automotive, datacoms/telecoms, instrumentation and power electronics manufacturers.

The SFBAC (combined Santa Clara Valley, San Francisco, and Oakland/East Bay) IEEE Power Electronics Society (PELS) for winning three 2017 Best Chapter Awards.