Patent ID: 8842225

Claim:
A switching power supply device, comprising: a reference voltage generation portion that generates a reference voltage; a ripple injection portion that uses a pulse voltage indicating on/off states of a switch device to generate a ripple component and injects the ripple component into the reference voltage; a multiplied voltage generation portion that generates a multiplied voltage in accordance with a multiplied value of an on-duty and an off-duty of the pulse voltage; a subtraction portion that pulls down, in accordance with the multiplied voltage, the reference voltage before ripple injection or a power supply voltage for a buffer that supplies the pulse voltage, which have a constant crest value, to the ripple injection portion; a comparator that compares a feedback voltage and the reference voltage after ripple injection with each other; and a switching control portion that performs on/off control of the switch device based on an output signal from the comparator to generate an output voltage from an input voltage in a non-linear control manner.