New DC/DC power technology aims to be the greenest yet

Power-supply technology has very quantifiable goals. Systems designers are increasingly driven to extract the most from the available technology in terms of energy efficiency, performance, power density, and cost.

•Energy-efficiency goals are driven by thermal considerations in the equipment that the power supply is to serve, by overall system manufacturing and operating costs and, increasingly, by government regulation.

•Performance goals for power supplies go well beyond providing the correct number of watts at a specified voltage; they span regulation over input and load range, dynamic response to load changes, and conducted and radiated noise.

•Energy density is a very critical system design goal in compact systems.

•Cost per watt has always been an important metric applied to the bill of materials of power systems and energy costs per year are now commonly quoted for systems that are powered on a continual basis. In many systems, the idle (standby) or low power energy usage is also a significant consideration in total energy usage. Modern power supplies have evolved to meet these goals, with DC-DC converters providing the underlying technology.

The development of packaged DC/DC converters, starting in the 1980s, was a huge step forward in the evolution of DC power technology. Like most revolutionary technologies, the first-generation of DC/DC modules had some serious limitations that were inherent in the design and also limited by components that were available to their designers.

Second-generation products attacked the efficiency, noise, and reliability issues with better components and better design.  Advances in semiconductor processes yielded MOSFET switches with much lower on-state resistance, resulting in decreased conduction losses.

A new circuit technique, dubbed a Sine Amplitude Converter (SAC), looks superficially similar in topology to the resonant converter, but its principles of operation are entirely different. Intermediate Bus Converters (IBCs) based on this new circuit technique achieve peak efficiencies of 98%. Unlike resonant converters, the Sine Amplitude Converter operates at a fixed frequency equal to the resonant frequency of the primary-side tank circuit.

To read the entire article, which discusses this approach in greater detail and which first appeared at EETimes-Europe, click here.

About the author

Bob Marchetti is Senior Manager of Product Marketing for the Brick Business Unit at Vicor Corp.  Marchetti holds a BSEE and an MBA and has been in the power supply industry for over 17 years.