| 摘要 |
PURPOSE:To suitably drive a semiconductor switch by providing forward bias current supplying means for positively feeding back to the base of a semiconductor switch by using a current transformer and forward bias current supplying means for supplying a current matched to the ON voltage of the switch. CONSTITUTION:A current flowed to a main circuit of a semiconductor switch 3 is detected through a current transformer 61 of the first forward bias current supplying means 6, and the output is positively fed back to the base of the switch 3. The second forward bias current supplying means 7 is provided in parallel with the first forward bias current supplying means 6, the ON voltage of the switch 3 is detected, and the current matched to the ON voltage is supplied through the base of the switch 3 in the forward bias direction. A reverse bias current supplying circuit 8 supplies a reverse bias current from a power source 83 to the base of the switch 3 by the negative signal voltage from an ON/OFF instruction unit 9. |
