Switching power supply apparatus

摘要

A switching power supply apparatus rectifies an AC power input in a rectifier circuit, switches a rectified output and rectifies and smoothes the same in a switching circuit, and a desired DC voltage is derived. A current limiting circuit limits a current supplied to a smoothing capacitor of the rectifier circuit. A voltage detecting circuit detects a rectified output of the rectifier circuit. A current limiting control circuit controls the current limiting circuit in response to a detected voltage. The current limiting control circuit activates the current limiting circuit in a first preset period in which the detected voltage is equal to or lower than a preset level. Further, the current limiting control circuit activates the current limiting circuit for a second preset period after the detected voltage is first changed from a level equal to or higher than the preset level to a level lower than the preset level and then returned to the level equal to or higher than the preset level.