INVERTER POWER SUPPLY CONTROL CIRCUIT OF HIGH FREQUENCY HEATER

摘要

PROBLEM TO BE SOLVED: To provide an inverter power supply control circuit of a high frequency heater which facilitates automatic resetting, and is capable of easily changing monitoring level at a low cost by considering characteristics of an IGBT element.;SOLUTION: At least one of a startup abnormality detecting part 31, a temperature abnormality detecting part 32, and a voltage abnormality detecting part 33 comprises a holding prevention circuit to prevent holding of detection state so that an input current abnormality based on oscillation stop due to abnormality detection is not detected by a current abnormality detecting part 34. So, after abnormality is settled, automatic resetting is easy without causing oscillation stop due to abnormality detection at the current abnormality detecting part 34. Since the power supply abnormality detecting part 30 is configured with an analogue circuit, a cost is lower and a monitoring level is easily changed. Only the monitoring level can be changed only for the temperature abnormality with the IGBT element 7.;COPYRIGHT: (C)2005,JPO&NCIPI