| 摘要 |
PROBLEM TO BE SOLVED: To stop oscillation of a magnetron by detecting an abnormal operation incurred in the magnetron without monitoring a current of a high voltage.SOLUTION: A power source for magnetron drive comprises: an inverter circuit 48 which supplies high frequency power to a magnetron 31 using a switching element 44; an input current detection circuit 52 which detects a primary current of the inverter circuit and outputs a voltage corresponding to the detected primary current; and a control circuit 50 for controlling the switching element. The control circuit includes: comparison means 78 for comparing a voltage value outputted by the input current detection circuit with a reference voltage 74 to control the switching element; and reference voltage switching means 71 for selectively switching to one reference from among a plurality of references prepared as the reference voltage. The reference voltage is switched during a shift period for shifting from a start time in which the magnetron starts oscillation to a normal time in which stable oscillation is started. |
