Patent ID: 7109780
Filing Date: 2006-09-19
Classification: H03K

Abstract:
1. A control circuit for an IGB transistor, comprising: means for generating an auxiliary voltage, the auxiliary voltage being generated so as to contain an intermediate voltage level to which an emitter or an auxiliary emitter of the IGB transistor is arranged to be connected; a first and a second controllable control switch configured to be responsive to control signals of the means for generating for controlling the IGB transistor to and from a conductive state, the control switches being coupled in series between the auxiliary voltage; and a gate resistor whose first terminal is connected to a point between the first and the second control switches and which is arranged to a circuit to be connected to a gate of the IGB transistor, wherein the control circuit further comprises: a boost capacitor connected in series with the gate resistor, a first terminal of the boost capacitor being connected to a second terminal of the gate resistor, and a second terminal of the boost capacitor being configured to be connected to the gate of the IGB transistor; a resistor whose first terminal is connected to the second terminal of the boost capacitor and whose second terminal is connected to the intermediate voltage level of the auxiliary voltage of the control switches; a Zener diode whose anode is connected to a point between the gate resistor and the boost capacitor and whose cathode is connected to a point between the boost capacitor and the resistor; and a diode whose anode is connected to the cathode of the Zener diode and whose cathode is connected to the positive terminal of the auxiliary voltage of the control switches.