| 摘要 |
PURPOSE:To prevent the applying of the excessive voltage between drain sources of the second self arc-extinguishing element by inserting and connecting the circuit to delay the turn-off action of the element into the junction capacity discharging path at the time of the turn-off of the second self arc-extinguishing element. CONSTITUTION:In the circuit to connect serially a MOS type FET 2 to a bipolar transistor 1 an the side of the emitter, a resistance 6 and the parallel circuit of a diode 7 are connected. For the turn-off of the MOS type FET 2 at the time of interrupting the bipolar transistor 1, the junction capacity through the resistance 6 between gate source is discharged, and therefore, the switching time is goes to be late. Consequently, the change of the negative electric current which flows at the MOS type FET 2 at the time of the turn-off is eased and the voltage impressed between the drain sources can be suppressed. |
