| 摘要 |
PROBLEM TO BE SOLVED: To obtain a stable high-voltage output of good controllability through the use of a piezoelectric transformer. SOLUTION: A piezoelectric transformer driving circuit 74 is operated by a driving pulse S72 output from a control section 72, then, the piezoelectric transformer 75 is driven by the piezoelectric transformer driving circuit 74, and an AC high voltage is output from the piezoelectric transformer 75. The AC high voltage is converted to a DC high voltage by a rectifier circuit 76. The DC high voltage is compared with a target voltage V53a output from a DAC 53a by an output voltage comparison means 78, then, the DC high voltage is controlled by the control section 72 so that the comparison result S78 obtains a rectangular wave. Accordingly, a stable constant voltage control becomes possible from a low high-voltage output to a high high-voltage output near the resonance frequency of the piezoelectric transformer 75. COPYRIGHT: (C)2010,JPO&INPIT
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