Switching power supply apparatus with overcurrent limiting and prolonged holding time

Abstract

A switching power supply apparatus including: a switching DC-DC converter for receiving an input voltage; a current detecting unit for detecting a current from the DC-DC converter; an input voltage detecting unit for detecting the decrease or cutoff of the input voltage; an overcurrent limiting circuit for stopping the operation of the DC-DC converter when the current detected by the current detecting unit exceeds a threshold; and a threshold control unit for changing the threshold of the overcurrent limiting circuit such that, if the decrease or cutoff of the input voltage is detected by the input voltage detecting unit, the period between the time when the decrease or cutoff of the input voltage is detected and the time when the operation of the DC-DC converter is stopped is prolonged.

Dependencies are inferred from the claim text.