TRANSISTOR-VOLTAGE DETECTING CIRCUIT OF TRANSISTOR INVERTER

摘要

PURPOSE: To decrease the wattage of a detecting resistor, to save a space and to improve detecting accuracy in the transistor-voltage detecting circuit of a transistor inverter, which is controlled by a base control signal having a dead time. ;CONSTITUTION: Differentiating circuits each comprising a resistor and a capacitor and photocouplers PC10-PC15 are connected across the emitters and the collectors of transistors 3u, 3v, 3w, 3x, 3y and 3z in series, respectively. Each of the photocouplers PC10-PC15 is driven at the rise time of the voltage across the collector and the emitter of each transistor. Of the transistors on the same arm of a transistor inverter 3, e.g. the photocoupler PC13 on the side of the transistor 3x, is driven. The applied-voltage detecting signal (VCEU) of the transistor is outputted during the period after the driving of the PC13 on the transistor 3x side to the driving of the photocoupler PC10 on the side of the transistor 3u. The detected signal is supplied into a dead-time compensating part 42.;COPYRIGHT: (C)1994,JPO&Japio