| 摘要 |
<P>PROBLEM TO BE SOLVED: To implement a drive circuit suited for driving of a normally-on-type semiconductor element that enters a conduction state when a negative potential is applied, without using a power supply dedicated for it. <P>SOLUTION: A source potential Vs of a high-speed switching element S by a p-channel-type FET on a feed line A is stepped down by a step-down resistor R1 and output to a gate G of the high-speed switching element S as a driving signal V<SB POS="POST">Go</SB>when nMOSFET5 connected between the step-down resistor R1 and a ground potential line B is on. The nMOSFET5 is turned on/off by a driving signal V<SB POS="POST">Gi</SB>for switching generated by a microcomputer of an auxiliary driving circuit 7 using a voltage of the feed line A (potential on the input side of a DC voltage Vi including more AC components than the high-speed switching element S). The microcomputer operates based on a constant voltage generated from the DC voltage Vi including the AC components of the feed line A. Therefore, a power supply dedicated for switching of the high-speed switching element S becomes unnecessary. <P>COPYRIGHT: (C)2012,JPO&INPIT |
