| 摘要 |
PURPOSE:To improve the gate turn-off capability by connecting a collector of the 1st NPN transistor (TR) and an anode of a diode and connecting the cathode of the said diode to the collector of the 2nd NPNTR. CONSTITUTION:A drive current source 25 is operated to turn off a thyristor 21 in on-state to drive NPNTRs 22, 23. As a result, a current is extracted from the P gate of the thyristor 21, which is brought into the off-state. In this case, a voltage between the P gate of the thyristor 21 and a negative power supply terminal 28 is lowered just before the OFF, since the diode 29 is inserted, no current flows from the base to the collector of the TR22 and the output current of the current source 25 is all fed to the base of the TR23. Then even after the operation of the TR22 is stopped, the operation of the TR23 is not attenuated and a high gate turn-off capability is realized. |
