For several years, “digital power,” defined as the digital control of power supply functions, was a solution in search of a problem. The concepts were well known and the benefits acknowledged, but applications remained elusive. Part of the problem was that it required learning a new – somewhat mysterious — way to design power supplies. And, there was the chicken-and-egg problem: New technology becomes cheaper as volume grows, but volume stayed low since adoption was slow.
That’s changing rapidly. First, there is increasing demand for complex power system management in new applications: Solar; Electric and hybrid vehicle charging; Smart Grid; LED lighting; Telecom infrastructure; Data center servers and many others.
The second impetus comes from the increased capabilities of mixed-signal semiconductor technology that integrates digital and analog circuits on one chip. Digital circuits can include logic, microprocessors and memory; analog circuits can be operational amplifiers, comparators, converters, pulse-width modulators and references. Such integration can cut component count, board size, bill of materials and can up reliability.
Integration can also provide many operational benefits:
Flexibility: On-chip MCUs can be programmed to support any of the major power topologies, as well as emerging ones.
Efficiency: Digital control can quickly adjust to changing line and load conditions to optimize both power and system efficiencies. For example, the control method of the power stage could be altered in real time for more efficient power transfer, or the power consumed in conversion can be adjusted to light or no load conditions.
System reliability and safety; Digital power devices can monitor and log diagnostic data throughout the host system over popular buses such as PMBus, and others.
Many engineers still view digital power as a daunting design task, but devices are now available in a variety of configurations (see “How To Select Digital Power ICs”) which allows designers to move into the digital realm at a pace commensurate with budgets, experience and project scope.