CURRENT DETECTION CIRCUIT

摘要

PURPOSE: To ensure reliable overcurrent protective operation by inserting a diode for compensating the temperature characteristics between the base or gate of a control transistor and the emitter of a shunt transistor and providing a forward bias through a resistor element constantly when a main current flows through the diode. CONSTITUTION: The anode-cathode of a diode 12 for compensating the temperature characteristics is connected between the base of an NPN transistor 3 and the emitter of a second IGBT 2. A resistor element 13 for forward biasing the diode 12 constantly when a main current flows through a first IGBT 1 is connected between the base of the second IGBT 1 and the base of the NPN transistor. This circuitry realizes temperature compensation of the threshold base-emitter voltage of a control transistor for detecting the voltage drop across a detection resistor.