Patent ID: 6922040
Filing Date: 2005-07-26
Classification: H02M,Y02B

Abstract:
1. A switching power source apparatus comprising: a switching output circuit for outputting a DC output voltage converted from a DC power source voltage by a semiconductor switch which is on-off controlled; error amplifying means for comparing said DC output voltage with a reference voltage to generate a feedback signal which decreases as said DC output voltage increases; a current detecting circuit for detecting an output current flowing through said switching output circuit to generate a current detecting signal which decreases as said output current increase; and a PWM comparator, to which said feedback signal and said current detecting signal are inputted as comparison signals and a triangular wave signal is inputted as a reference signal, for comparing a lower signal of said comparison signals and said triangular wave signal to output a PWM signal, wherein said semiconductor switch is on-off controlled by said PWM signal and the current detecting circuit performs a straight current limit operation having a predetermined gradient while an output current is from a current limit operation starting current value to an output current maximum value, when the output current is beyond the current limit operation starting current value.