Patent ID: 8143867
Filing Date: 2012-03-27
Classification: B60Q,H02H,H03K,H05B

Abstract:
1. An electric power supply device comprising: a semiconductor element; a power source having a positive terminal to which a first main electrode of the semiconductor element is connected through a wiring of a power source side; a load connected between a second main electrode of the semiconductor element and a ground; and a control portion that controls the semiconductor to be turned on and off to supply an electric power to the load, wherein when a first voltage of a point between the first main electrode and the wiring of the power source side is lower than a first decided voltage, the control portion controls the semiconductor element to be turned off, and the control portion controls the semiconductor element to be turned on when a first prescribed time is elapsed after the semiconductor element is turned off; and wherein when the semiconductor element is turned on after the first prescribed time is elapsed so that a minimum value of the first voltage exceeds the first decided voltage, the control portion controls the semiconductor element to continue a turning on state, and when the first voltage is lower than the first decided voltage, the control portion controls the semiconductor element to hold a turning off state.