| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that a piezoelectric transformer is controlled by a frequency lower than a resonance frequency and a desired high output voltage is not obtained in the case of wanting to obtain the high output voltage around the resonance frequency of the piezoelectric transformer, in a high voltage power unit using the piezoelectric transformer. <P>SOLUTION: A high voltage power unit 60 includes a primary transfer voltage preparation circuit 70-1 for supplying, to a load, the output voltage of a piezoelectric transformer 72-1 which is driven by oscillation signals outputted from a CPU 61 and outputs the output signals of a high voltage when the frequency of the oscillation signals is in a neighborhood of the resonance frequency. The load state of a temperature and a humidity or the like is detected by load state detection means, the lower limit of the variable range of the frequency of the oscillation signals is set by the CPU 61 corresponding to the load state of the temperature and the humidity or the like, the output voltage to be outputted to the load is detected, and the frequency of the oscillation signals is varied in the direction of canceling a difference between the output voltage and a target voltage. <P>COPYRIGHT: (C)2012,JPO&INPIT |
