Patent ID: 7545129

Claim:
A switching power supply circuit having switching means and an inductor for converting a direct current input voltage into a direct current output voltage, comprising: an error amplifier for outputting an error signal representing a differential voltage between a preset reference voltage and a voltage based on the direct current output voltage; a PWM comparator for outputting a switching signal for on/off control of the switching means at a predetermined duty ratio determined by comparing the error signal with an oscillation signal outputted by an oscillation circuit; current detection means for detecting a current flowing through the switching means or the inductor; current holding means for holding the current flowing through the switching means or the inductor over a past predetermined period; and current superposition means for adding a current superposition signal to an output of, or an interior of, the error amplifier, the current superposition signal making an adjustment, based on a present current information signal which is an output signal of the current detection means, such that an ON-period of the switching signal of the PWM comparator is shortened, and also making an adjustment, based on a past current information signal which is an output signal of the current holding means, such that the ON-period of the switching signal of the PWM comparator is lengthened.