| 摘要 |
An RF generator power supply comprises a first switched mode power supply (SMPS) 42 connected in series to a second SMPS 44 by a DC bus. A capacitor 43 is arranged between the outputs of the first SMPS and inputs of the second SMPS to act as a smoothing capacitor for the first SMPS and to supply pulse energy to the second SMPS. The second SMPS has an output connected to an input of a step-up transformer 45 and an output of the step-up transformer is connected to an input of a rectifier 46 connectable to the RF generator 48. An input of the first SMPS is connectable to a prime power supply to maintain a high power factor with low harmonic content while setting an operating voltage and peak current level for the RF generator. The second SMPS is arranged to feed the step-up transformer and is arranged to operate with a variable duty cycle and/or variable frequency to provide average power control of the RF generator. The second SMPS is rapidly switched off on detection of a power surge through the RF generator. |
