| 摘要 |
<P>PROBLEM TO BE SOLVED: To restrain the switching loss or the surge voltage of a drive circuit for voltage-driven elements from increasing due to the variation of its threshold voltage. <P>SOLUTION: The drive circuit for voltage-driven elements comprises a turn-on time measuring means 11 and a turn-off time adjusting means 12. The latter means 12 corrects the gate discharge rate of the voltage-driven element IGBT (Q1) at turning off to correct the turn-off time so that the gate discharge rate at turning off decreases with the increase of the turn-on time and vice versa, and the former means 11 measures the turn-on time based on a voltage across a capacitor C1 for charging it during turning on. It comprises a PNP transistor (Q3) an emitter terminal and a collector terminal of which are connected to the gate of the IGBT (Q1) and the ground, respectively. The capacitor C1 is connected to the base of the PNP transistor (Q3). <P>COPYRIGHT: (C)2004,JPO |
