| 摘要 |
PROBLEM TO BE SOLVED: To provide a limiting circuit which can achieve a short-circuit resistant property by a method in which a diode is connected in series with a gate resistor, a clamping diode is connected in parallel with the resistor in such a way that its cathode becomes the side of an emitter and a diode for draining is connected to every gate in such a way that the cathode becomes the side of a gate power supply. SOLUTION: In a limiting circuit, an intrinsic gate resistor is installed at every IGBT module, and a gate resistance Ron at a time when an IGBT is turned on is different from a gate resistance Roff at a time when the IGBT is turned off. Then, the interaction between gate terminals is prevented by a diode which is connected in series with the low-ohmic gate resistance Ron for turning-on, and a high-speed expitaxial diode whose parasitic capacitance is small is favorable as a diode at a gate circuit. In addition, in order that a gate voltage which is higher than a power- supply voltage at a drive stage is not generated due to the counteraction of the internal capacitance of the IGBT, a drain diode is installed so as to be added to the power- supply voltage at every module. As a result, the short-circuit resistant property of the limiting circuit can be achieved. |
