Patent ID: 8125206

Claim:
A semiconductor device included in a switching power supply which drives to turn on and off a semiconductor switching device connected to a DC power supply in series to supply a predetermined constant voltage to an external load, the semiconductor device comprising: a semiconductor circuit which controls on and off data states of the semiconductor switching device, wherein an output voltage of the switching power supply or a divided voltage obtained by dividing the output voltage at a predetermined ratio is used as a feedback voltage, wherein a pulse-width modulation signal is generated by comparing the feedback voltage and a set voltage, and wherein in one switching cycle in which the output voltage, the divided voltage, a difference voltage between the output voltage or the divided voltage and the set voltage, or an error voltage obtained by amplifying the difference voltage exceeds a first threshold voltage, a PWM on-pulse of a pulse-width modulation signal for turning the semiconductor switching device to the ON state is generated twice.