Patent ID: 8519748

Claim:
A driving circuit for driving a transistor comprising: a control circuit, wherein the transistor includes a control electrode, an output electrode and an input electrode, the control circuit controls a control electrode resistance of the transistor based on a control current flowing through the control electrode of the transistor, the control circuit controls the control electrode resistance of the transistor based on a predetermined threshold of the current, the control circuit controls the control electrode resistance of the transistor based on the control current when a charge accumulated in the control electrode of the transistor is being discharge, the control circuit controls the control electrode resistance to decrease when an absolute value of the control current is large, the control circuit controls the control electrode resistance to increase when the absolute value of the control current is small, the control circuit includes an adjustment transistor and a resistor, the resistor has a resistance which is larger than an on-state resistance of the adjustment transistor, the adjustment transistor includes a control electrode, an output electrode and an input electrode, the resistor is disposed between the control electrode and the input electrode of the adjustment transistor, the resistor is coupled with the control electrode of the transistor, the adjustment transistor is turned on and off in accordance with a voltage difference generated between both ends of the resistor, the adjustment transistor is turned on so that the control current of the transistor flows through the adjustment transistor when an absolute value of a control current of the transistor is large, the adjustment transistor is turned off so that the control current of the transistor flows through the resistor when the absolute value of the control current of the transistor is small, the adjustment transistor is a P conductive type field effect transistor, the input electrode of the adjustment transistor is coupled between the resistor and the control electrode of the transistor, and the output electrode of the adjustment transistor is grounded.