White Paper: Power

Efficient Power Supply Burn-in Using Regenerative Electronic Loads


Switch-mode power supplies used in data centers, industrial equipment, medical devices, and other critical applications are typically subjected to burn-in operation at full load over an extended period to root out early failures and ensure reliable operation over the supply’s rated lifetime. The traditional method of conducting these tests utilizes relatively inexpensive resistive load banks that convert the power output to heat. The heat generated in the load banks is dissipated using either fan (air) or water cooling. Consequently, the energy costs of conducting the burn-in far exceed the power output of the power supplies under test.

Traditional load banks, basically an array of power resistors, offer an inexpensive hardware solution for product burn-in. In some situations, where a small number of units are being tested and/or where a separate room is used for the tests, the load bank can be a clear, economic choice. Electronic loads, in contrast to passive load banks, typically employ active circuitry to dynamically simulate changing load profiles. As such, electronic loads, while they can be used to simply perform a static long-term burn-in, can also subject the devices under test to step changes in the power demand and other variations in the characteristics of the load, thus providing a more reliable result of the tests. Standard electronic loads, however, still suffer from the problem of what to do with the heat generated and loud fan noise.

The introduction of regenerative electronic loads has dramatically altered the economics of power supply burn-in testing. This application note describes how the use of advanced-technology, regenerative electronic loads resulted in energy cost reductions exceeding 90%. In addition to the lower energy costs, the use of regenerative loads has also resulted in improved factory floor space utilization, reduction in electrical distribution infrastructure, reduced ambient noise, and lower environmental cooling costs.

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