| 摘要 |
PURPOSE:To shorten the voltage drop time at turn-off and to reduce the tail current value without an increase in the turn-on loss and in the power loss accompanying a forward voltage drop by a method wherein the absolute value of an off-gate power source voltage, whereat a breakdown voltage between an anode.emitter layer and N-base layer is higher than the breakdown voltage between a cathode.emitter layer and P-base layer, need not be set to have specific relations with other voltages. CONSTITUTION:When a positive off-gate power source voltage E1 and negative off-gate power source voltage E2 are applied, suction of electrons is accomplished by a first gate electrode 16 in a GTO element 1 and, at the same time, suction of holes is accomplished by a second gate electrode 18. Under the conditions, a conductive region is squeezed in an N-base layer 11 and P-base layer 12, whereby injection of holes out of an anode.emitter layer 13 and that of electrons from cathode.emitter layer 14 are placed under control. With the off-gate power voltages F1 and E2 are so set as to satisfy an inequality ¦E1¦ > ¦E2¦, the maximum off gate current IGP1 involving the first gate electrode 16 will be larger than the maxim off-gate current IGP2 involving the second gate electrode 18. |
