Drive circuit for a field effect-controlled power semiconductor component

摘要

A voltage source provides an input signal to a drive circuit for a power semiconductor. A protective circuit is connected between the drain and the source of the power semiconductor and is activated when excess current is present. The protective circuit provides an output signal that is received by a control circuit to limit the voltage at the gate of the power semiconductor. The control circuit is connected between the gate and the source. A controllable resistance including an enhancement MOSFET and an external capacitor in which the enhancement MOSFET has a gate, a source and an internal capacitance between the gate and the source is connected in parallel to the external capacitance. The controllable resistance carries the input signal from the voltage source to the power semiconductor. The controllable resistance is switched to high impedance when the protective circuit is activated and switched to low impedance when the protective circuit is deactivated.