Patent ID: 7592853
Filing Date: 2009-09-22
Classification: H03K

Abstract:
1. A drive circuit for an insulated gate device comprising: a constant current source that generates a constant current; and a switching circuit, wherein a gate of the insulated gate device is connected to a power supply potential side via the constant current source at the time of turn-on and the gate of the insulated gate device is connected to a ground potential side at the time of turn-off; wherein the constant current source comprises a first transistor including a drain side is coupled to a resistor, a second transistor which is configured as a current mirror circuit along with the first transistor and which generates the constant current determined by the value of the resistor and a reference voltage, and a third transistor which is configured as the current mirror circuit along with the second transistor and including a drain which is connected to the gate of the insulated gate device; and wherein the constant current source includes a bias circuit which the voltage substantially according with a gate voltage of the insulated gate device is applied to a drain of the first transistor.