| 摘要 |
PROBLEM TO BE SOLVED: To provide a high frequency heating device reducing voltage stress and thermal stress of a semiconductor switch element installed in a main power amplifier and enhancing reliability. SOLUTION: A power detecting circuit 8 measures incoming power transmitted from the main power amplifier 6 to a load side and reflecting power reflected from the load side, and when incoming power is increased and a matching state is not maintained, decreases output voltage of a DC voltage source 7, and controls the output voltage of the DC voltage source 7 to a second setting value. Thereby, the voltage stress and the thermal stress of the semiconductor switch element installed in the main power amplifier 6 are reduced, and reliability is enhanced. COPYRIGHT: (C)2005,JPO&NCIPI
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