GaN pumps power revolution

-January 30, 2015

Those who say 'don’t bet against mainstream silicon CMOS technology' haven’t heard what’s going on in gallium nitride.

An emerging class of GaN power chips is finally knocking down the final cost barriers to their adoption. The chips will enable a wide range of applications from wireless charging to autonomous vehicles and more efficient cellular communications, said Alex Lidow in his DesignCon keynote.

“The apps are so numerous I could list them for half an hour,” said Lidow (below), chief executive and co-founder of Efficient Power Conversion Corporation (EPC). “Many of our products today are already lower cost than [rival] silicon power MOSFETs, and we are already moving quickly down the cost curve.”

Higher costs of epitaxial process makes EPC's largest products more expensive than rivals. However, that cost will get shaved by next year, he said, noting all EPC’s products will be lower cost than silicon rivals in 2016.

The fast switch EPC gets on its proprietary GaN process allows significantly higher efficiency than today’s silicon parts. The fact that the devices do not require a package adds to their prowess, something that happened almost by accident.

“When we were starting the company, I went to all the big packaging suppliers but they didn’t want to deal with us because we were so small, so I said, ‘to hell with it,’ and we got rid of the package,” he told an audience of several hundred engineers at DesignCon.

Now EPC has more than 500 customers with several products in high volume production. Later this year, the company plans to roll out higher power RF FETs and ICs up to 6 GHz as well as a fifth generation of its core power conversion chips.

“We are doubling our capability every year, and that will continue for the foreseeable future -- we are a 1,000× from our known limits,” said Lidow, who developed the HEXFET power MOSFET in 1978 at International Rectifier and later served as the company’s CEO for 12 years.

The GaN chips will be key enablers of the Rezence version of wireless charging. The devices help systems stay tuned to the resonance needed for wireless charging. “You didn’t see this until 2015 because it was hard,” said Lidow citing forecasts of a $10 billion wireless charging market by 2018.

The chips also speed fixes for LiDAR devices that use light to estimate distance in systems ranging from cars to virtual-reality headsets. “The rise and fall times of GaN devices is a tenth of silicon MOSFETs -- that’s key,” he said.

The chips will also play a role making cellular networks more efficient. Their switching speed helps reduce wasted power in cellular base stations and satellite communications.

The chips are also seeing use in a broad range of applications including power supplies for network gear and servers, Class-D audio systems, high res MRI systems, AC adapters, and robots.

The fast switching time may generate more electro-magnetic interference, one expert said. However, EPC has clearly passed FCC tests on a variety of products to date. Its technology has already attracted competition from many companies now working on GaN power chips.

It’s rare to see anything that beats CMOS, but “we are on a very fast track to making our parts more efficient than MOSFETs,” Lidow said.

GaN chips can switch 5-8× faster than silicon MOSFETs, according to Lidow.

A look at two interesting apps

GaN chips will enable the Rezence approach to letting loosely coupled devices charge wirelessly, Lidow said, outlining the approach (above).

Separately, cellular networks will benefit from the fast switching time of GaN chips to increase the power efficiency of some devices they use that are currently as low as 25% (below).

For more from DesignCon -- the premier event for the chip, board, and system design community -- click here.

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