Semiconductor device including over voltage protection circuit having gate discharge circuit operated based on temperature and voltage as to output transistor

摘要

A semiconductor device includes an output transistor which controls a power supply to a load according to a control voltage applied to a gate thereof, a voltage control circuit coupled between the gate and a drain of the output transistor, the voltage control circuit having a conduction state controlled according to a potential difference between a source and the drain of the output transistor, and a voltage control detection circuit which outputs a voltage control detection signal on a basis of the conduction state of the voltage control circuit. A first discharge switch is connected between the gate and the source of the output transistor, an on-off state of the first discharge switch being controlled according to the voltage control detection signal, a second discharge switch is series-connected to the first discharge switch between the gate and the source of the output transistor, an on-off state of the second discharge switch being controlled according to a temperature condition of the output transistor, and a third discharge switch is connected in parallel with the first and second discharge switches.