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IN THIS ISSUE:
» Using Forced-Frequency Resonant Zero-Voltage Switching In USB PD Adapters
» Using Local Energy Storage For Organized System Shutdown Simplifies Power Supply Hold-Up Time Requirements
» A Flexible Design For Fast Charging Supercapacitors In Industrial Applications
» New on How2Power.com
FAE Confidential
» Focus On Magnetics:
Why Magnetics Design Has Progressed So Slowly
» Spotlight On Safety & Compliance:
Keeping Up With IEC 62368
» New Power Products
» Industry Event:
- ECCE Plenaries Explore Battery Health Estimation, Hybrid/Electric Propulsion In Aviation And More
» Other Top Power News
From the Editor's Desk David G. Morrison
Editor, HOW2POWER TODAY
It’s been only a few years since power IC makers started introducing controllers and reference designs to address the versatile USB Power Delivery (PD) specification, which supports output voltages from 5 V to 20 V at up to 100 W. Now, as the application of USB PD continues to take hold in adapters, it’s driving the development of power supply ICs using innovative techniques to optimize performance. In this issue, an article by Jimmy Wang discusses the use of forced-frequency resonant zero voltage switching in DCM-operated flyback converters to enable more efficient, high frequency switching in USB PD-based adapters. This article highlights how a number of industry trends can come together to address the needs of high-volume power supply applications—high switching frequency, digital control, multiple operating modes and use of planar magnetics. All that’s missing is a GaN power switch, which we have seen in some other adapter designs. The standardization afforded by the USB PD spec and the associated Type C connector should give power IC developers plenty of incentive to keep crafting more intelligent and efficient power supply controllers for years to come. This issue also presents a feature on using local energy storage to ease bulk cap requirements in server power supplies, some application examples of supercapacitor fast charging, a look at factors that may be holding back progress in magnetics design, a review of IEC 62368, the latest power components and other news.
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HOW2POWER EXCLUSIVE DESIGN ARTICLES 
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Using Forced-Frequency Resonant Zero-Voltage Switching In USB PD Adapters
by Jimmy Wang, Infineon Technologies, Shenzhen, China
Capable of supplying anything from 5 to 20 V and supporting power levels up to 100 W, USB-C cables may be the only thing we need to power our laptops, as well as to connect a wide range of peripherals to them. It also breaks the previous 7.5-W power limit at 5 V, opening up the possibility of charging smartphone batteries even faster. This article discusses some of the challenges in designing USB PD-based power adapters and how they can be addressed using a switching technique known as forced-frequency resonant zero voltage switching (ZVS) in a DCM-operated flyback topology. A reference design based on a controller developed to implement this technique, the XDPS21071, is presented, its principles of operation and other circuit details are explained, and a prototype and measurements of its efficiency are provided and discussed.
Read the article…
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The forced-frequency resonant form of ZVS
supports operation at frequencies above
100 kHz, enabling use of a planar
transformer embedded in the pc board. |
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As the percentage of total power
needing to be buffered is reduced
and the allowed voltage droop is
increased, the capacitor required for
secondary-side energy storage
becomes smaller than that required
for primary-side energy storage. |
Using Local Energy Storage For Organized System Shutdown Simplifies Power Supply Hold-Up Time Requirements
by Viktor Vogman, Power Conversion Consulting, Olympia, Wash.
Traditionally, the energy needed for organized system shutdown is stored in the PSU bulk capacitor, which supplies power to the entire system during an ac fault event. When warning and/or hold-up time needs to be significantly extended (5 to 10 ms) for organized shutdown mode, a straightforward solution is to increase the PSU bulk cap size. But this greatly increases power supply size and cost, especially in server redundant subsystems using two or more PSU modules. This article studies an opportunity for easing the PSU hold-up time requirements for applications that require significantly extended warning time intervals. It shows how a local buffer cap can supply power just to the components critical to the organized system shutdown while increasing system immunity to indiscriminate power faults.
Read the article…
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A Flexible Design For Fast Charging Supercapacitors In Industrial Applications
by Nazzareno (Reno) Rossetti and John Woodward, Maxim Integrated, San Jose, Calif.
With their short charge and discharge cycles, supercapacitors require chargers that can handle high current. The chargers must work smoothly in constant current (CC) mode during a charge, which often starts at 0 V, and in constant voltage (CV) mode once the final output value is achieved. In high-voltage applications, many supercapacitors are connected in series, requiring chargers to manage high input and output voltage. In this article, the authors discuss two use cases for supercapacitors: automatic pallet shuttles in storage facilities and short-duration backup systems in fail-safe valve actuators. They then introduce a synchronous stepdown supercapacitor charger (the MAX17701) that can handle a large number of industrial and consumer applications, using the two use cases to demonstrate its capabilities.
Read the article…
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In the event of a power failure,
a string of 10 supercaps
delivers 10 A to power an
actuator. |
NEW ON HOW2POWER.COM
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FAE Confidential
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In FAE Confidential, we present the final installment in the series by the OT club: “The War On FAEs (Part 3): Management Shifts To Active Aggression.”
See FAE Confidential.
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FOCUS ON MAGNETICS
Sponsored by Payton Planar Magnetics
A monthly column presenting information on power magnetics design, products, or related technology |
Why Magnetics Design Has Progressed So Slowly
by Dennis Feucht, Innovatia Laboratories, Cayo, Belize
This article contrasts the development of the magnetics industry, particularly power magnetics as applied in electronic power supplies, with that of the semiconductor industry by giving an overview of the history of each. The objective of this comparison is to analyze why the semiconductor electronics technology has grown so much quicker than the magnetics technology. Why have the theory, terminology and industry practices underlying power transformer and inductor design and development for power electronics failed to keep pace with that of power semiconductors and ICs, and semiconductors in general?
Read the full article…
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SPOTLIGHT ON SAFETY & COMPLIANCE
Sponsored by Power Integrations
A monthly column discussing standards and regulatory requirements affecting power electronics |
Keeping Up With IEC 62368
by Kevin Parmenter, Chair, and James Spangler, Co-chair, PSMA Safety and Compliance Committee
The UL/EN/IEC 62368 standard is a merger of two standards—UL/EN/IEC 60065 Audio and Video Equipment and UL/EN/IEC 60950 Information and Communication Equipment. Most designers probably have some familiarity with 62368 because the industry has been transitioning to this standard for several years. There’s another regulatory milestone looming as the legacy standards in the European Union are about to be withdrawn on December 20, 2020. As this deadline approaches, many designers may still need to come up to speed on what the standard requires, and understand what variations of the standard are being applied as well as aspects of the standard that are still in flux. With that in mind, we present a brief overview and update on UL/EN/IEC 62368.
Read the full article…
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 — POWER PRODUCTS IN 3 IMAGES OR LESS
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INDUSTRY EVENT |
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ECCE Plenaries Explore Battery Health Estimation, Hybrid/Electric Propulsion In Aviation And More
ECCE 2020 has announced the speakers for its virtual plenary session on October 12. This session will feature talks on “The price of degradation—The value of prognostics—Opportunities and Needs in Battery Health Estimation,” “NASA Aeronautics Strategies for Hybrid/Electric Propulsion and Transforming Aviation,” “Current and Future Outlook of Hydrogen Fuel Cell on Multiple Market Sectors,” and “System Operations—Defenders of the Grid—Past, Present, Future”. For more about these talks and the distinguished speakers who will be giving them, see the conference website.
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 UnitedSiC, a manufacturer of SiC power semiconductors has entered into a distribution agreement with Macnica, a distributor of semiconductor products in Japan.
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