Rudy Severns: Lifetime Achievement Award Winner

Sep 1, 2008 12:00 PM
By David Morrison, Editor in Chief

In Boredom, Inspiration

“In 1980, while working for Intersil, I wrote the first tract on how to invent new topologies. I wrote what's called the kama sutra of power-supply topologies. It's a 40- or 50-page application note full of dozens and dozens of circuits. And a lot of them are new or showing likeness between old ones. The whole idea was here's how you invent power-supply topologies.”

“I had given a couple papers before touching on the subject. Topology invention for me really started when I worked at Hughes and I never let that thread go. So for Intersil, I wrote this humongous application note for SMPS people saying here are all the ways you can use it. Of course, all of the models in there use MOSFETs for switches, naturally. Ed Bloom looked at that application note and said, ‘Couldn't we write a book on that?’”

After that suggestion, some time passed and Severns embarked on his sailing trip to Mexico and Hawaii. Severns notes that normally he could forget about engineering for several months at a time, but that was more difficult to do on such a long voyage.

“So, I'm on my cruise, and it's about seven or eight months into the cruise. I'm in Kane'ohe Bay, Hawaii. I'm sitting in paradise absolutely bored to death. So I say, ‘Ed, I am going to write a book.’ And I sat down with a pencil and a pad of yellow-lined paper on the boat and wrote in longhand everyday for a few hours.”

“And then I just kept mailing these packages to Ed Bloom, one chapter at a time. His wife, Joy, is transcribing on an early Apple computer. She is taking all of this chicken scratch on yellow-lined paper and writing this all up. Then Ed goes through and checks everything.” Out of this work emerged Modern DC to DC Switchmode Power Converter Circuits.

“The book would not have happened without Ed Bloom's efforts. He prodded me to write it. He did a tremendous amount of work, about 80% of the work. And Ed added a chapter 12 on converters with integrated magnetics.”

Severns says he was amazed at the reception the book received. “We have sold several thousand copies, and it has been translated illegally into several languages. It's not the world's greatest technical book at all, it's just sort of a show and tell,” says Severns. “But the main comment I got back was how easy it was to read and create new ideas from. That was part of the reason for its success. The other part was that there was nothing like it other than the application note I had written at Intersil.”

“Engineers working in the field were choosing power-supply topologies from a very, very narrow set at the time, and we just wanted to jog them a little bit. Now, given the experience over the past 25 years since the book was written, having hundreds of circuits has only had a small impact on the field,” comments Severns. “People are still using the same relatively small set of topologies for large commercial activities (i.e., high-volume, low-cost products). The book really had its impact in more specialized military, space and medical applications.”

At the time he wrote the book on topologies, Severns was well into his career as an independent consultant. In that role, he continued to give seminars, write papers and participate in industry conferences.

New Engineering Challenges

A few years ago, Severns took down his consulting shingle and retired. But for Severns, retirement has given him an opportunity to pursue his interests in amateur radio more intensively. His involvement with power electronics and amateur radio, he believes, are closely linked.

“Certainly for me, they're one item, a single thread, really. All of my early work stems from being a teenager trying to build a transmitter. That's all analog, and with transmitters you're immediately into high voltage and high power. Today, the theme continues as I'm doing a lot of experimental electromagnetics work in antennas.”

Severns has been busy publishing his results in various amateur radio magazines and also on his Web site. But ultimately, he'd like to make a contribution to the amateur radio field by writing a book in which he explains details surrounding the operation of vertical antennas, grounds and ground antennas. Within these topics there are issues that have either been “misexplained, ignored or are matters of contention,” says Severns.

To support these endeavors, Severns has gone back to school. For the last four years, he has been taking courses in mathematics and electromagnetics at the University of Oregon to bring himself up to speed on the field.

And despite his attempts to retire from power electronics, just this year he completed a book on snubber design at the urging of Jerrold Foutz, a longtime industry veteran. The book, Snubber Circuits for Power Electronics, explores an area of power-supply design that is absolutely critical in high-power applications.

And while he views himself as being out of the power electronics business these days, Severns may yet take some of the knowledge he has “salted away” and write additional books on power design topics. If he does, it will be another opportunity for Severns to influence future generations of engineers working in the power electronics field.

With demands for energy efficiency driving technology development and applications like smart power grids emerging, Severns believes “power electronics is alive and well.”

“There's a whole field available to young engineers,” says Severns. “Everywhere I look, I see opportunities.”

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