| 摘要 |
PURPOSE:To prevent the increase in a switching loss at the voltage drop of a 2nd drive power supply for turning-off by reducing a current when an IGBT is turned off. CONSTITUTION:This circuit is provided with a 1st drive power supply 1 to send an ON-voltage from a gate pulse transmission circuit 3 and with a 2nd drive power supply 2 to send an OFF-voltage from the gate pulse transmission circuit 3, a voltage detection circuit 4 detects the voltage drop of the relevant 2nd drive power supply 2 to interrupt a feeding path from the 1st drive power supply 1 to the relevant gate pulse transmission circuit 3. Thus, the 1st and 2nd transistors(TRs) are driven by a gate pulse from the gate pulse transmission circuit to turn on/off an IGBT, then the current at turn-off is especially reduced and the feeding path of the 1st drive power supply to the gate pulse transmission circuit is interrupted at the voltage drop of the 2nd drive power supply to turn off the IGBT, then the increase in the switching loss of the IGBT is prevented. |
