New-Tech Europe | December 2016 | Didital Edition

Power Modules - In Search of a Winning Combination

Jon Cronk, Exar Corporation

Equipment designs increasingly utilize advanced MCU, DSP and FPGA devices to deliver the functionality and performance demanded of them. With this sophistication comes the challenge of providing the multiple power rails these devices require. The use of carefully chosen power modules can significantly ease this task and allow system designers to get to market on time and without compromise. A quick examination of almost any piece of industrial and telecommunications equipment will clearly show that it requires a large number of individual DC bus voltages operating at different currents to provide power to all the sub-circuits in the design. Each DC bus voltage is typicallysuppliedbyaDC-DCswitching

time and cost are rare commodities. A “Wish List” for the ultimate power system design From a cursory analysis of subsystem power requirements it is a short step to identifying a wish list for an ideal power delivery solution, which must: 1. Meet the most stringent specifications of the subsystem, e.g. voltage tolerance. 2. Operate with the highest possible efficiency - this allows battery- powered devices to last longer and reduces power dissipation so that devices can run cooler and be more reliable. Every 10C rise in operating temperature halves the Mean Time Between Failure (MTBF). 3. Provide excellent transient response for FPGA and CPU operation to avoid spurious operation caused by false clocking or incorrect power sequencing. 4. Offer a programmable output

regulator or an LDO that has to fit in ever smaller PCB footprints and yet meet tighter and more demanding performance specifications relating to efficiency, input and output voltage regulation, and operating temperature, to mention a few. These specifications are necessary to ensure the equipment can operate for longer, run cooler and achieve higher reliability. In order to design these converters in-house, electronic equipment companies must employ highly qualified and experienced power engineers and, depending on the number of converters needed, allow sufficient time in the project schedule for the design and prototyping of the power system, including full test and verification. This is a process that is expensive and time consuming, impacting both the project budget and time-to-market in a very competitive market where

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