| 摘要 |
PROBLEM TO BE SOLVED: To prevent the deterioration of the circuit efficiency of a power unit by using a first DC power supply as the driving power supply of a converting means and a second DC power source as the driving power supply of a driving device and, at the same time, providing a first detection circuit which controls the output voltage of the second DC power supply by detecting the voltage across both ends of a coil for supplying high-frequency power. SOLUTION: A first DC power supply E1 which inputs the DC voltage output of a rectifier DB1 that rectifies AC power AC is used as the driving power supply of a main amplifier 7 which is a power converting means and a second DC power supply E2 which inputs the DC voltage output of the rectifier DE1 is used as the driving power supply of a driving device 9. A first detection circuit 10 controls the output voltage of the power supply E2 by detecting the voltage across both ends of a coil 2 for supplying high-frequency power. Therefore, the deterioration of the circuit efficiency of a power unit can be prevented. |
