Making the Technology Count

Lots of people involved in the global electronics industry will already have read about the resignation of Alex Lidow, PhD, as CEO of International Rectifier. The news and views on what prompted his departure have received considerable coverage from the media, but I don’t want to go into that here.

Alex Lidow’s importance as far as this magazine and its design engineering readers go is what he brings to the world in terms of innovative, ground-breaking electronics technology.

I have been fortunate enough in my job to spend time with Alex Lidow. I’ve listened to his talks about International Rectifier’s technological developments and the compelling reasons why we humans have to take every ecological advantage provided by power-management technology.

Alex Lidow has crystal-clear vision on this point and the development of that vision is captured by some of his previous comments to Electronic Design magazine:

“Imagine you needed a glass of water and the only way to fill it up was from a fire hydrant with a big, clunky valve. Sure, you’d get that glass filled with water—but the street would be filled as well. In the good old days, transistors that turned on and off energy were as clunky as that big valve on the fire hydrant,” explains Lidow.

THE FAST VALVE
Lidow and Tom Herman changed all that back in 1978 with the HEXFET power MOSFET. Together they were able to develop an extremely fast valve to turn on and off the water— that is, energy—one drop at a time. Therefore, you could then fill up your cup without wasting any one drop of it. The end result was that we saw an entirely new world of energyconserving appliances.

At the insistence of his father Eric Lidow (who founded International Rectifier) to focus on semiconductors, Alex Lidow attended California Institute of Technology. “My first class was with James W. Mayer, a most inspiring professor. I fell in love with his subject—semiconductors,” recalls Lidow.

After graduation, Lidow proceeded on to Stanford for further studies in semiconductors. It was there, explains Lidow, where a “catalytic event happened.” Professor Dick Swanson asked if we knew what made his eyeglasses cost what they cost. He said “it was the energy it took to make them and bring them to us. Energy had to melt the glass and create the frames. Energy heated the store where they were sold. Energy refined the gas running the worker’s car.” Geopolitics may set pricing, explains Lidow, but the cost of everything is directly tied to the cost of energy.

Lidow and classmate Tom Herman realised that there was a way to make a rather large impact on energy conversion. Back in the mid-1970s, energy was electrically converted via a linear power supply, linear amplifiers, and electromechanical motor drives. The problem was that there was no way to adjust the energy load. Excess energy was simply being burned off as heat.

So, Herman and Lidow made a pact to work on this problem. Herman, who was ahead of Lidow in school, went to International Rectifier to work on field-effect transistors (FETs) “because they could switch energy quickly.” Lidow followed in 1977.

They used FETs to replace linear power conversion with switch-mode power conversion. It increased efficiency from 30% or 40% to 80% and 90%. Then they decided to use metaloxide- semiconductor field-effect transistors, or MOSFETs.

PRETTY GOOD TRANSISTOR
In November 1978, they came out with the MOSFET. “It was a pretty good transistor,” says Lidow. Then Tom had a flash of insight. “If we applied a geometric structure like a honeycomb to the silicon chip, we could pack a lot more power-handling capacity into a small space. That actually improved the chip by a factor of four.”

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It was enough to change the power MOSFET from a premium/ unique product to one that could address the needs of the entire marketplace. It would be like making a Cadillac at the cost of a VW. First conceived in late 1978, it was introduced on June 9, 1979 and it just took off from there.

“But that’s the beginning of the story rather than the ending. Once we enabled switching power conversion, it opened up a whole world of opportunity,” says Lidow.

“People around the world use 404 quadrillion BTUs of energy each year. That’s what sets the global standard of living. We spend it making cars, making glasses, growing food. If we could do more with the same amount of energy, we could live better.”

So International Rectifier took the MOSFET, took high-performance analog circuits, added speciality software, and created variable-speed motors.

“The trick was to deliver variable- speed motors at no extra cost to the consumer, but allow us to make a profit,” remarks Lidow, and that was ultimately accomplished.