Patent ID: 8242830

Claim:
A power supply control circuit comprising: an output transistor of an N-channel type provided between a power supply line and an output terminal; a gate driving circuit generating a control signal for controlling on/off of the output transistor based on an external input signal; a first discharge path including a first depletion-type N-channel MOS transistor provided between a gate and a source of the output transistor and, when turning off the output transistor, operable to discharge a charge stored in the gate of the output transistor based on the control signal; and a second discharge path including a second depletion-type N-channel MOS transistor provided between the gate and the source of the output transistor and, when turning off the output transistor, operable to discharge a charge stored in the gate of the output transistor more slowly than the first discharge path, wherein the first discharge path further includes a discharge cutoff circuit coupled to the first depletion-type N-channel MOS transistor in series between the gate and the source of the output transistor, in the case of turning off the output transistor, operable to detect that the gate voltage of the output transistor has fallen to a prescribed voltage level, and operable to cut off discharging a charge stored in the gate of the output transistor.