Digital Power: Still Looking For A Killer Application

Apr 18, 2007 10:54 AM
By Alan Elbanhawy, director in the Advanced Power System Center, Fairchild Semiconductor International, San Jose, Calif.

In 2005, I presented a conference paper^[1] in which I argued that the power-supply industry would only switch from analog PWM controllers to fully digital controllers if a killer application were found. Here it is two years later and the killer app has yet to be identified — but why?

The sought-after killer app would be one where a digital power converter can offer needed performance benefits and flexibility, and where no analog solution can be easily and elegantly achieved. This combination of factors, together with the right price, would lure the industry’s executives and procurement managers to accept digital power.

While there have been some impressive strides toward these goals since 2005, there has been no mass adoption of digital power technology in any application that would signal a turning point for the power-supply industry. So what has been holding digital back? Is the killer application idea still valid?

The question of whether digital power needs a killer app to succeed is somewhat controversial. Shortly after I published my conference paper, I remember reading an article that questioned the relevance of a killer application. The author argued that no single application is large enough to cause an industry-wide migration from analog to digital control.

But I maintain that the dc-dc converter used to power the CPU in personal computers (PCs) would be an ideal killer application for digital. There are about 200 million such power converters manufactured every year, and these converters must meet some of the most demanding specifications in the industry.

Most of these power converters now employ analog control. But if the digital approach were to achieve great success in this area, it would almost guarantee that the technology could be easily adapted to all other dc-dc applications. This is true because, to get universal approval in the PC market, a PWM controller must meet all the CPU’s demanding performance specifications at a price that is at least on par with the ubiquitous analog solution.

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© 2007 Penton Media, Inc.