Impact of Burn-In on Power Supply Reliability

Focus:

Burn-in tests weed out infant mortalities for power supplies in production and provide data that can be used to improve the reliability of the power supplies. The standard approach in the power supply industry has been to operate the power supplies at high temperature, under full load with power cycling, and with input voltage set to either the specified maximum or minimum value, depending one whether maximum voltage stress or maximum current stress is desired. However, there are a number of other burn-in techniques that may be applied, which may be used to stress components that are not sufficiently stressed by the standard burn-in approach, or to speed test time, or save energy. These various techniques are described, and their advantages and disadvantages are discussed. The article also discusses the use of highly accelerated stress screen (HASS) and highly accelerated life test (HALT) in combination with burn in. The eventual elimination of burn-in for those products that exhibit low levels of burn-in failures is also discussed. The article discusses how measures of reliability such as failure rates per 10^9 hours of operation (FITs) and mean time before failure (MTBF) are determined and how those parameters affect decisions to eliminate burn in.

What you’ll learn:

• How to perform power supply burn-in and other forms of reliability testing
• How to shorten test time for power supply burn-in
• How to reduce energy consumption associated with power supply burn-in

Notes:

Note from the editor: Power supply burn-in seems to be viewed as proprietary knowledge by power supply manufacturers. That a manufacturer such as C&D Technologies (now part of Murata) wrote at length about their approaches to burn-in testing would seem to make this article particularly valuable, especially to those who are new to power supply manufacturing.

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Author & Publication:

Don Gerstle, Vice President of Global Quality and Reliability, C&D Technologies, Power Electronics Division, Tucson, Ariz., and Paul Lee, Director of Engineering, C&D Technologies, Power Electronics Division, Milton Keynes, U.K., Power Electronics Technology, Sep 01 2005

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