Don Alfano, Director of Applications Engineering at Silicon Labs tells a story from the point of view of - the power supply - and you get to see what pressures are placed on these almost invisible products, and what Joe Power Supply needs to keep up with technology changes.
Joe works in the power supply industry where each day he is faced with a few undeniable market trends. The physical size of electronic systems shrinks every year. This alone makes system power supply harder. But wait, there's more...
At the same time, the capabilities of these systems increase while market price is flat at best or possibly even lower than the introduction price of the previous generation. Obvious examples of this are high profile consumer items like cell phones; more subtle examples are items such as servers, routers and industrial systems. We've heard the pitch a million times: "This new (fill-in-the-blank) is smaller, faster, has better features and (oh, yes) it is the same price as last years model, and if you act now, we can offer you a rebate..." So the manufacturers of these products must pack more features into less space in each new product generation. That is a tough design task and the last guy who gets budget and space allocation is Joe power supply designer who does the circuits that power this contraption.
People select one electronic product over another based on its perceived value, and that value has to do with the primary functions the product provides. For example, one typically buys a TV based on the screen size, video and sound quality, connectivity, etc. One rarely chooses a TV based on what kind of power supply it has inside. That's another downer for Joe Power Supply.
Because the new-fangled electronic contraption has all these new features, the system requires more power. And, because the latest low-voltage semiconductor technology is used in the creation of this stuff, the electronics are increasingly more sensitive to the voltages the power supplies provide. So guess what that means for Joe? The power supply design specs he gets will be more stringent with each new product generation.
So, Joe is getting squeezed on space, performance, power density (less space, more Watts), cost and, since everything is getting smaller leaving less room for heat removal, operating efficiency. Joe has to do more and more with less and less until he will be asked to do everything with nothing. With me so far? Good. Now let's peel the onion one more layer.
So what does Joe Power Supply have in his arsenal in the way of technology to meet these daunting challenges? Good question. Joe has what amounts to "modernized" versions of traditional analog functions that have the same basic architectures that existed back when Moby Dick was a minnow. These components are "tried-and-true" solutions to traditional power supply problems, but it is getting harder and harder for Joe to meet his supply design requirements. These architectures are too big, use too many different components, have problems reacting to sudden increases and decreases in power demand, tends to not age gracefully because they're made from analog components whose values fluctuate with age, temperature and other environmental conditions and are difficult to test and even more difficult to repair. In short, it's not exactly an optimum solution, but it's been used for so long, it is "just the way it is done."
Think about what's important to Joe: size, cost, efficiency, ease-of-design, reliability and performance. These are all "non-fluffy" quantities...I mean, these attributes don't come easy. No wonder Joe lost his hair and stomach lining long ago. So how do we help Joe? What remedy can we offer him? How can we help Joe just...get along?
Well, what Joe needs is a modern digital control system in his supply. One that uses modern digital processing technology to eliminate the coffee cans full of analog discrete parts that the analog supply design demands. One that has a more intelligent system interface so it can anticipate changes in system operating conditions and use this information to proactively optimize its operation. Intelligent power supply control will be smaller because it does not need the coffee can full of analog stuff and more efficient because its digital "brain" can adjust system parameters to optimize efficiency at any given load. It will be lower cost because its intelligence can assist in self-test for lower test cost, improved reliability, fewer field returns and lower BOM. It will be easier to design because it is programmable and best of all " it will enable Joe to stay on the design cost curve effectively.
Yes - digital control, Joe. That's the ticket! It is the future of power supply technology. You'll be a happy man, Joe, and you can finally live a normal life.
Don is Director of Applications Engineering for Silicon Labs and you can reach him at Don Alfano.