| 摘要 |
<P>PROBLEM TO BE SOLVED: To surely prevent an excessive current at turn off of a small current. <P>SOLUTION: A gate driving circuit 20 is supplied with a control signal Sa via an insulator 10, and the junction between gate resistors 13 and 15 is connected to the gate of an IGBT5a. The gate driving circuit 30 is composed of a reference power source 31 for setting a first reference value Vref1, a comparator circuit 32 which compares this first reference value Vref1 with the gate potential of an IGBT5a, an AND circuit 33 which performs the AND operation between the output of this comparator circuit 32 and the switching signal S2 for switching on or switching off a switch circuit 14, and a flip flop 34 which has a set terminal (S) and a reset terminal (R). It operates to switch on the switch element 22 and keep it after the control signal Sa to the gate driving circuit 20 is switched into an OFF command. <P>COPYRIGHT: (C)2007,JPO&INPIT |
