Feature

Measure power-supply-loop transfer

Using a function generator and an oscilloscope, you can measure gain and phase shift versus frequency in a power supply's control loop.

By Frederik Dostal, National Semiconductor -- EDN, 12/5/2008

Power supplies use control-loop circuits to produce constant voltage or current. The transfer function—gain and phase as a function of frequency—provides valuable information about a control loop’s speed and stability. Knowing a control loop’s transfer function, as well as the poles and zeros of the transfer circuit, can help you select the right compensation and power-stage components.

This article originally appeared in the September 2008 edition of EDN's sister publication, Test & Measurement World. Please click here to view the rest of the article, including the Web-only sidebar and video referenced in the EDN print edition.