PFC Takes The Stress Out Of Power ApplicationsSponsored by: FAIRCHILD SEMICONDUCTOR

Feb. 3, 2005

Conventional offline switch-mode power converters create nonsinusoidal input currents with a high harmonic content. This causes stress for the power wiring, circuit breakers, and electric utility. In addition, these harmonics can affect other electronic equipment connected to the same power line. Active power factor correction (PFC) that reshapes the input current before its application to the switch-mode supply solves this problem.

PFC has become important since the European Union established the EN61000-3-2 Standard and Amendment A14 for electronic equipment. This standard limits allowable ac line current harmonics. Limits depend on the input power, type of product, and specific harmonic. See the table for a list of the original equipment classifications and the Amendment A14 classifications. Class D limits are of major interest because they cover PCs, computer monitors, and television receivers. Other devices must only meet Class A limits.

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About the Author

Sam Davis 2

Sam Davis was the editor-in-chief of Power Electronics Technology magazine and website that is now part of Electronic Design. He has 18 years experience in electronic engineering design and management, six years in public relations and 25 years as a trade press editor. He holds a BSEE from Case-Western Reserve University, and did graduate work at the same school and UCLA. Sam was the editor for PCIM, the predecessor to Power Electronics Technology, from 1984 to 2004. His engineering experience includes circuit and system design for Litton Systems, Bunker-Ramo, Rocketdyne, and Clevite Corporation. Design tasks included analog circuits, display systems, power supplies, underwater ordnance systems, and test systems. He also served as a program manager for a Litton Systems Navy program.

Sam is the author of Computer Data Displays, a book published by Prentice-Hall in the U.S. and Japan in 1969. He also authored the book Managing Electric Vehicle Power. He is also a recipient of the Jesse Neal Award for trade press editorial excellence, and has one patent for naval ship construction that simplifies electronic system integration.

You can also check out additional articles on his other author page.