THYRISTOR SWITCH DRIVING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To prevent an anode current or cathode current from varying owing to the addition of the gate driving current of a thyristor switch held at a floating potential. SOLUTION: A thyristor switch driving a circuit comprises a P gate thyristor switch 71 held at a floating potential, a 1st current mirror circuit 5 which is equipped with a current input circuit 5a and a current output circuit 5b and outputs a current equal to the current inputted to the current input circuit from the current output circuit, a constant current circuit 4 which supplies an ON driving current turning on the P gate thyristor to the P gate terminal of the P gate thyristor switch through the current input circuit of the 1st current mirror circuit, and a 2nd current mirror circuit 6 which has its current input circuit 6a connected to the current output circuit of the 1st current mirror circuit and its current output circuit 6b connected to the cathode terminal of the P gate thyristor, and is characterized by that the current equal to the current supplied to the P gate terminal of the P gate thyristor switch is led out of the cathode terminal of the P gate thyristor.