HOW2POWER TODAY

ISSUE: July 2020

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IN THIS ISSUE:

» Analysis, Simulation And Experimentation Enable Successful Design Of Power Supply Compensation

» Different Approaches To Learning And Applying Digital Signal Processing In Power Electronics

» Focus On Magnetics:
Interstitial Wire Interleaving Packs More Conductor Into Magnetic Windings

» Spotlight On Safety & Compliance:
Mounting Bridge Rectifiers: Compliance Needs Make It Complicated

» New Power Products

» Other Top Power News

Electronics technology is continually evolving and advancing with new components, instruments and design tools to aid engineers in meeting new design goals. Several of the innovative components in this month’s Power Products section attest to this ongoing progress. Even in midst of the pandemic, component development and product launches proceed unabated. Some examples reported in this issue include a fully integrated voltage regulator IC, SiGe rectifiers, and a better rad hard MOSFET package. However, efforts to better understand and explain basic engineering concepts and design tasks, also evolve as evidenced by our two design features. Christophe Basso’s article on designing power supply compensation, reviews this familiar topic with a tutorial that explains in detail multiple ways to analyze and simulate the response of a power stage, tips on applying the three types of compensation, and advice on verifying the compensator design with a prototype and further analysis. While many of these techniques have been discussed before, new treatments of the subject like Basso’s help to illuminate aspects that may have been neglected in previous works, and reflect the author’s vision of how to tie the information together. Certainly, Dennis Feucht’s feature on digital signal processing does some of the latter, as he compares the different ways that the DSP subject has been explained in different math and engineering disciplines, helping engineers to grasp the connections between the various methods and how they are best applied (conceptually) in power electronics. He also reviews the classics of DSP literature, giving engineers guidance on which references have stood the test of time in explaining the subject. Enjoy these and other articles in the July issue.

HOW2POWER EXCLUSIVE DESIGN ARTICLES

Analysis, Simulation And Experimentation Enable Successful Design Of Power Supply Compensation

by Christophe Basso, ON Semiconductor, Toulouse, France

Loop control represents an important aspect of the design of a switching power supply. However, for various reasons, its study is often relegated to the end of the project when the main components have already been selected. Through simple trial and error, it is sometimes possible to get the impression that a design delivering an acceptable transient response on the oscilloscope is ready for production but this is a very unwise and potentially costly attitude. Without a thorough analysis backed up by simulations and loop measurements, you have no idea what phase and gain margins look like and how solid they are. It is very likely that such a loosely designed converter will fail in production or shortly after being powered in the field. To keep you away from such situations, this article reviews some of the tools currently available to let you calculate, simulate and measure your prototype’s control loop before safely pressing the production start button. Read the article…

Once you have the transfer function
magnitude/phase plot in hand for your
power stage, you can think of a
compensation strategy consisting of
placing poles, zeroes and gain (or
attenuation) at various frequency
locations to meet your design goals

A “mixed-waveform” analog and
digital system with a sampled
feedback loop such as might be
found in a digitally controlled power
supply. ADC and DAC are sample-
hold components that convert
between ratios of digital counts and
voltage ratios.

Different Approaches To Learning And Applying Digital Signal Processing In Power Electronics

by Dennis Feucht, Innovatia Laboratories, Cayo, Belize

One of the early confusion factors in learning digital signal processing (DSP) is the rather different emphases placed upon it in DSP books. If you learn DSP from a book like the Prentice-Hall classic, Digital Signal Processing, by Oppenheim and Schafer (or from Alan Oppenheim’s excellent MIT video course), or even more so, from another Prentice-Hall book, Digital Filters, by R.W. Hamming, you will get a filter-oriented view of DSP. On the other hand, if you learn it by reading digital control books, you will acquire a control-oriented view. And more basically, if you learn it by reading numerical analysis books of mathematics, you might wonder how it is related to electronics (or engineering). What then is the best approach to an efficient acquisition of the subject? In this article, the author explores this issue from a power electronics perspective. Read the article…

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

Interstitial Wire Interleaving Packs More Conductor Into Magnetic Windings

by Dennis Feucht, Innovatia Laboratories, Cayo, Belize

One of the limitations on winding efficiency is the packing factor, k_p, the fraction of winding area that is conductor. Ideally the conductive part of a winding—the copper or aluminum part of the wire turns—would completely fill the area allotted to a particular winding, and the current and power density would then be maximum. However, gaps between round wires result in areas not conducting current. This article proposes a way to reduce gaps and thus increase the winding fill factor, k_f by filling these gaps with smaller wires. After reviewing the various packing factor components that quantify winding density, we’ll analyze how to determine the optimum wire size for the smaller wire in square-layered and hexagonal-layered winding configurations. We’ll also determine the improvement in fill factor obtained in each case. Read the full article…

One possible way to alleviate the
packing factor problem is to fill in
the gaps between adjacent wires
in a layered winding with
smaller-sized wire

SPOTLIGHT ON SAFETY & COMPLIANCE       
Sponsored by Power Integrations
A monthly column discussing standards and regulatory requirements affecting power electronics

Mounting Bridge Rectifiers: Compliance Needs Make It Complicated

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

Among the various types of semiconductor devices, bridge rectifiers are somewhat unusual in that they are subject to safety agency certifications such as UL. These devices have agency approvals because they often connect to the ac mains in their applications. In addition, higher-power bridge rectifiers are usually mounted on a chassis or heatsink, such that they become part of the isolation safety barrier and therefore subject to creepage and clearance considerations as well as hi-pot testing. There are also maximum touch temperatures that affect rectifier usage. The requirements for isolation and heat removal are often in conflict. This article discusses techniques and strategies for satisfying these requirements—real world best practices—and highlights some of the pitfalls to avoid when mounting bridge rectifiers in your applications. Read the full article…

  — POWER PRODUCTS IN 3 IMAGES OR LESS

OTHER TOP POWER NEWS

Efficient Power Conversion (EPC) and VPT have announced the establishment of EPC Space, a joint venture focused on designing and manufacturing radiation hardened GaN-on-silicon transistors and ICs, which are packaged, tested, and qualified for satellite and high-reliability applications.

The IEEE Nuclear & Space Radiation Effects Conference (NSREC), which had been postponed from July to December 2020, is transitioning to a virtual event..

Vicor, a provider of high-density and high-efficiency power management solutions, has joined the Global Semiconductor Alliance.

ROHM and LEADRIVE have established a joint laboratory to co-develop SiC-based automotive inverters.

LoadSlammer, Steve Sandler and Picotest have formed a joint venture to develop a family of the world’s fastest GaN-Based slew rate testers.

Cree is donating $3.5M to support a STEM education program for the SUNY Polytechnic Institute as part of a long-term commitment to help expand the local economy in New York’s Mohawk Valley and develop a pipeline of high-tech professionals.