Patent ID: 6831821
Filing Date: 2004-12-14
Classification: H02H,H03K

Abstract:
A semiconductor switching device comprising:a multi-source field effect transistor including a main source electrode having a main source potential and a reference source electrode having a reference source potential; a voltage comparator for detecting whether the main source potential is lower than the reference source potential: a gate driving circuit including the multi-source field effect transistor in an ON state when the main source potential is higher than the reference source potential, and in an OFF state when the main source potential is lower than the reference source potential based on the voltage comparator detection; a reference current setting circuit for feeding a reference current including a constant component current and a transient component current to the reference source electrode so that the main source potential is not lower than the reference source potential, and so that the transient current component starts to be fed whenever the voltage comparator detects that the main source potential is lower than the reference source potential; a counter for counting the number of vibrations of the main source potential to a predetermined number of times on the basis of the detecting of the voltage comparator, and the gate driving circuit turns OFF the multi-source field effect transistor when the counter exceeds the predetermined number.