Patent ID: 8116051

Claim:
A power supply control circuit, comprising: a first and second power supply lines, a power supply voltage being applied between the first and second power supply lines; an output transistor coupled between the first power supply line and an output terminal; a first switch coupling the first power supply line with a control terminal of the output transistor when a counter electromotive voltage from a load, which is connected to the output terminal, is applied to the output terminal; a switching element coupling the second power supply line with the control terminal of the output transistor when the power supply voltage is applied in a reverse direction between the first and second power supply lines; and a reference voltage control circuit applying a potential corresponding to a potential of the second power supply line to a reference voltage node coupled to a control terminal of the first switch when the power supply voltage is applied in a forward direction between the first and second power supply lines, and that applies a potential corresponding to a potential of the first power supply line to the reference voltage node when the power supply voltage is applied in the reverse direction between the first and second power supply lines.