Patent ID: 8604769

Claim:
A switching power source device comprising: a switching power source portion of a nonlinear control method to generate an output voltage from an input voltage by performing an ON/OFF control of a switch element according to a comparison result between a feedback voltage and a reference voltage, wherein a ripple component is injected to either one of the feedback voltage and the reference voltage; and an offset control portion to adjust either one of the feedback voltage and the reference voltage for cancelling a DC offset of the output voltage caused by the ripple component, wherein the switching power source portion comprises: a reference voltage generator to generate the reference voltage; a ripple injection portion to generate the ripple component based on a switch voltage generated at one end of the switch element and to inject the ripple component to the reference voltage; a comparator to compare the feedback voltage with the reference voltage to which the ripple component is injected; and a switching controller to perform an ON/OFF control of the switch element based on an output signal of the comparator, and wherein the ripple injection portion comprises: a first amplifier having a non-inverting input terminal connected to an input terminal of the reference voltage before a ripple injection, and having an inverting input terminal connected to an output terminal of the first amplifier; and a pulse driver connected between an inverting input terminal of the first amplifier, an output terminal of the first amplifier, and an input terminal of the switch voltage.