POWER SUPPLY DIAGNOSTIC SYSTEM

摘要

A power supply includes a digital controller (10) which generates pulse-width modulated control signals for controlling the duty cycles of switching transistors (36) for the purpose of regulating the output voltage of the power supply. The controller (10) incorporates a diagnostic system which includes a plurality of comparators (297) arranged to compare each of a number of voltage level signals representing operating conditions at portions of the power supply with a reference voltage, and logic circuits (330-348) responsive to the outputs of the two comparators for generating an output identifying an element of the power supply which has failed. This output is stored and is displayed in a LED display (154) which is actuated by operation of a switch member (360). Integrated circuit chips may be used in the controller so that the diagnostic system is of simple construction and of low cost.