POWER FACTOR CORRECTION CIRCUIT WITH OVERCURRENT PROTECTION

摘要

The invention relates to a circuit for switching a DC power supply apparatus. The circuit short-circuits and opens an AC voltage supplied from an AC voltage source (1) through an inductive element (2) using a switching means (4), at least once in a half-cycle period of the AC voltage, in order to convert the AC voltage supplied from the AC voltage source (1) to a DC voltage. The switching means (4) is short-circuited for a predetermined time period prior to the switching means (4) commencing a switching operation after switching on, and a current detecting means (3) detects a current flowing through one of the inductive element (2) and the switching means (4). The switching operation is not commenced if a magnitude of the detected current value is greater than a predetermined current level, thereby protecting an apparatus when the inductive element (2) is in an abnormal short-circuiting state.