Patent ID: 8482272
Filing Date: 2013-07-09
Classification: G05F,H02M,Y02B

Abstract:
1. A DC-DC converter comprising: a power supply input unit to which a direct current voltage is input; a power supply output unit from which a direct current voltage is output; a series circuit including a main switch element and a sub switch element; an inductor including an end connected to a connection point between the main switch element and the sub switch element; and a capacitor that is connected to the power supply output unit; wherein the DC-DC converter is arranged to perform conversion on a DC voltage input to the power supply input unit and supply a DC voltage to a load connected to the power supply output unit; the DC-DC converter further comprises: a drive circuit that outputs a drive signal to the main switch element and the sub switch element; a pulse generating circuit that outputs a pulse signal to the drive circuit; and a sub switch control signal generating circuit that generates a sub switch control signal to prevent reverse flow of a current through the inductor at a time of a light load; wherein the sub switch control signal generating circuit includes a detection capacitor, a charging/discharging circuit that charges/discharges the detection capacitor in accordance with switching periods of the main switch element and the sub switch element, and a sub switch control signal output circuit that outputs the sub switch control signal based on a potential of the detection capacitor.