Insulated gate-type bipolar transistor.

摘要

To provide an insulated gate-type bipolar transistor with an overcurrent limiting function that is capable of keeping the ratio of a main current to a detection current constant even under different operating conditions, and is capable of suppressing the voltage dependence of the value of the limited current to perform stable overcurrent protection, P-wells (9) are formed so that they are incorporated between main cell IGBTs (6) as sensing cells for current detection on part of the semiconductor substrate (5) on which a large number of main cells are formed integrally, and current-detecting emitter electrodes (10) connected to the P-wells are connected to an overcurrent-protection circuit and separated from the main emitter electrodes (7) connected to the main IGBT cells. Given such a configuration, the overcurrent flowing into the main cells during a load short circuit in an inverter device is accurately detected as a hole current from the P-wells with the current ratio to the current in the main cells remaining constant, and moreover, stable overcurrent protection is performed keeping the limited current values suppressed below the short-circuit withstand capability without dependence on the power supply voltage. <IMAGE>