Drive manner of DCAC inverter and temperature protection network null of DCAC

摘要

PROBLEM TO BE SOLVED: To provide a temperature protection circuit for a DC-AC inverter which prevents a semiconductor switching element from breaking by heat. ;SOLUTION: An H bridge circuit 10 is equipped with the first to fourth semiconductor switching elements SW1-SW4. Thermistors 22a and 22b detect the temperature of the second to fourth semiconductor switching elements SW2-SW4. A temperature judging circuit 24 outputs an operation stop command signal SC to a switching control circuit 24 when the semiconductor switching elements SW2 and SW4 come to the reference voltage or over. The switching control circuit 24 turns off the first to fourth semiconductor switching elements SW1-SW4, in response to the operation stop command signal SC.;COPYRIGHT: (C)1999,JPO