(Editor's note: while this article is admittedly a biased perspective in favor of digital power control, it contains some very good insight into what DPC is and the benefits it offers. Your comments and "rebuttals" are welcome below, of course.)
Digital power has come out of the realm of R&D lab and into the main stream. In recent years digital power has made great strides, offering performance improvements previously not attainable. Note that the term “digital power” is often loosely defined with respect to power supplies. Sometimes the term “digital power supply” refers to merely a power supply which is digital, otherwise known as a switching power supply. This type of supply may utilize either digital or analog methods to control the on/off time of the power MOSFET. Also, analog power-supply controllers may make use of digital circuitry for power supply sequencing and tracking, voltage margining, as well as I2C implementations or reading back of fault conditions, such as input/output undervoltage and overvoltage, or output short circuit.
However, the use of such digital circuits does not make an analog power IC digital power. How the power-supply ICs feedback and control loop is implemented determines whether the power-supply IC is an analog- or a digital-power IC.
The digital power this paper refers to is when the feedback and control loop in a power supply is implemented using digital algorithms. In this paper we will first explore the difference between analog and digital power supplies, followed by the benefits derived from digital power supplies.
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About the author: Zahid Rahim is the vice president and general manager of the AC/DC business unit at iWatt, Inc (Los Gatos, CA). Prior to joining iWatt in 2008, he was the General Manager of the Power Management division at Integration Associates. Zahid’s previous experience includes Director of Marketing for the Power Management business unit at Impala Linear (acquired by Fairchild). He also spent nine years in applications engineering and marketing roles at National Semiconductor. Zahid started his career as an IC design engineer at Philips Semiconductor, and holds an MSEE degree from Columbia University and a BA in Physics and Mathematics from Wartburg College, Iowa.