| 摘要 |
PURPOSE:To suppress a current loss by adding a transistor and a diode to a turn OFF driving circuit of a GTO, and providing a current pulse switching circuit. CONSTITUTION:A driving circuit for a gate turn-OFF thyristor (GTO) 2 has a low voltage diode 64, a high voltage diode 65, a current pulse switching circuit 83 and an OFF transistor (Tr) Q70, etc. A Tr Q40 connected between the P-gate 23 and a ground potential 10 so as to extract a current from a P gate 23, the Tr Q70 connected between the P-gate 23 and a cathode 24 so as to short-circuit the P-gate 23 and the cathode 24 are provided, the bases of the Trs Q40, Q70 are controlled by a turn OFF pulse signal 82 through the switching circuit 83, thereby controlling to shift the GTO 2 from ON to OFF. Thus, when the cathode potential of the GTO 2 is reduced to a predetermined value, the Tr Q70 is automatically turned ON, thereby continuing the extraction of the current. |
