| 摘要 |
PURPOSE:To increase a turn-OFF gain by setting the finger voltage of an auxiliary thyristor so that it becomes higher than the finger voltage of a main thyristor. CONSTITUTION:The main thyristor consisting of a P type emitter layer 5, an N type base layer 6, a P type base layer 7 and an N type emitter layer 8 is connected to a main circuit, and the auxiliary thyristor composed of the layers 5, 6, 7 and an N type emitter layer 10 is connected between the anode and gate of the main thyristor. When the minimum value (the finger voltage) of voltage between an anode and a cathode necessary for bringing the auxiliary thyristor to an ON condition is made higher than the finger voltage of the main thyristor and the main thyristor is turned ON, the auxiliary thyristor is turned OFF. The P type emitter layer 5 of the auxiliary thyristor is surrounded by an N type layer 12 having high impurity concentration for that. Or the N type emitter layer 10 is made thinner than the N type emitter layer 8. |
