Patent ID: 7391199

Claim:
A DC-DC converter comprising: a high-side switch connected to the power supply voltage side, a low-side switch being used for rectification and connected to the ground side, an inductor, one terminal of which is connected to the connection point of said high-side switch and said low-side switch connected in series, an output filter, one terminal of which is connected to the other terminal of said inductor, and the other terminal of which is grounded, and a current detection circuit that detects the current flowing through said low-side switch, wherein said DC-DC converter is configured to adjust the current flowing through said low-side switch and to control the output voltage being output from said output filter by turning ON/OFF said high-side switch and said low-side switch; said current detection circuit is configured to detect current flowing through said low-side switch in both a first direction and a second direction when said low-side switch is ON; and said current detection circuit comprises: an auxiliary switch that turns ON when said low-side switch is ON, and a compensation circuit that adjusts the current flowing through said auxiliary switch so that the voltages of said low-side switch and said auxiliary switch are equal when said low-side switch and said auxiliary switch are ON.