I've just returned from the first annual Embedded Power Conference in San Jose and a major theme was rise of digital power control (DPC), what it takes to achieve it, and the potential benefits it offers both supply designers as well as those designing the larger system into which the supply goes. (You can read my EPC report here).
Coincidentally, I received a call last week from a “market analyst” who said he had heard that “digital power” was the next big thing, what did I think? And more importantly to him, did this mean that traditional analog power-IC companies would be losing those markets?
I gave the analyst my usual response: don't know, can't say. Frankly, I resent that these analysts expect me (or you) to tell them what we know and learned the hard way over many years, so they can re-sell that information for big bucks; there are ethical issues as well, with me giving my opinion in ways that may affect the public perception or stock price of various vendors. I have no qualms about being “not helpful” to these know-little, talk-big market analysts!
The reality is that DPC is coming on, and coming on strong. For supplies above the smallest capacity, say, 50-100 W, it is becoming cost competitive. But to me, the real benefit of DPC is not cost, nor that it allows improved control-loop algorithms compared to fixed-component, analog designs. The real plus is that it allows much better monitoring of the supply's performance, in both steady-state ongoing data-collection mode to assess impending failures, as well as high-speed data logging, as a sort of flight-data recorder black box, to see how well the supply is doing versus the load situation, and to have a better data on supplies which are returned to the factor as “bad” but for which no faulty can be found (the dreaded NFF label).
If you step back and look at what a DPC circuit requires, it is no surprise: it takes a lot of analog circuitry. You need one or more ADC functions (different sample rates and resolutions), interface circuitry to monitor multiple voltages, current, and temperature points, and perhaps circuitry to monitor the input side, whether AC or DC sourced. This is where analog vendors, both established and newer ones, will have an important role.
This storyline of “things are going digital, what's going to happen to analog?” is not a new one. I hear it every few years when an existing analog technology becomes digitized, such as broadcast TV or radio, or even cell phones. The irony and opportunity is that the more digital system implementations there are, the more it takes analog circuitry to make it happen, whether it be for the external I/O, or for internal drivers, signal integrity, and power sources.
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