| 摘要 |
PURPOSE:To embody a radio frequency power supply whose protective circuit does not function against an overcurrent having a quick rise which is caused by a load fluctuation. CONSTITUTION:The set value P of a third set signal source 17 is predetermined at a value lower than a radio frequency output value P0 which is controlled by a reference signal source 7. Therefore, as a signal value from a coupler 5 is higher than the set signal value from the third signal source 17, a third comparator 16 turns on a transistor T3 and short-circuits the output of a second comparator 10 to prevent a relay 13 from operating. In this state, an overcurrent having a quick rise is applied by a load fluctuation at a time T1 and the current value exceeds first and second set values I1 and I2. Although an output which drives the relay 3 is generated by the second comparator 10, as the radio frequency output is higher than the set value P, the relay 13 does not operate, so that the supply of the radio frequency output to a load is not discontinued. |
