US Patent 7768759 Control circuit of semiconductor device having over-heat protecting function

A control circuit of a semiconductor device includes: a semiconductor element which supplies an electric power to a load; an over-heat protecting unit having: a temperature detecting section which detects a rise in temperature; a latch section which holds an output of the temperature detecting section; and a gate interrupting section which interrupts an input to a gate of the semiconductor element in accordance with the output of the latch section; a control unit which supplies a PWM signal for turning on/off the semiconductor element; a driving electric power supply unit which supplies a driving electric power for driving the over-heat protecting unit; and a timer unit which allows the driving electric power supply unit to supply the driving electric power for a predetermined period when the input to the gate of the semiconductor element is interrupted and the control unit stops to supply the PWM signal.