Powering up digital

Digital power has been grabbing more and more attention without proportionate market share. In 2005 IEEE conducted a survey to find whether digital power will become a significant market opportunity. Nearly 60 percent of respondents said they expected to use digital power in future. However, digital power is far from making any significant dent in analog power market share.

The issue is not of technology but of price. There is hardly any doubt that digital power is a better solution than analog one. Its ability to change parameters easily such as the loop compensation and thereby withstand wider load changes is now well established. Better yields and lower testing costs are other advantages. Ease of communication, programmability, status reporting are yet other benefits.
The superior technology could not offset the price advantage of traditional analog power. However, this year end digital power is projected to achieve price parity with analog power, which should see the former coming into its own from next year. Darnell estimates that the market for digital power ICs will grow at a CAGR of 36.4 percent from $169 million in 2006 to $796 million in 2011.

Other factors are also emerging that should see digital power taking strides. Power converter companies are increasingly bringing out products incorporating digital power management and control IC solutions, both hybrid (digital and analog) and digital. In power conversion applications, a microcontroller-based digital architecture provides a lot of flexibility especially in applications wherein besides programmability, current- and voltage-profiling are also required.

Analog die size shrinks 30 percent every generation, and cost is halved every 4 to 8 years. But for digital, die size shrinks two times with each new generation, which is 18 to 24 months, resulting in better economies, estimates Darnell. However, the cost of each new generation is 10 to 20 percent higher, so it takes two to three years for digital to reduce cost two times.