| 摘要 |
PROBLEM TO BE SOLVED: To detect an output voltage without deteriorating the control accuracy of an output current. SOLUTION: A voltage detection electrode 11 detects an electrostatic induction voltage Vs by an output voltage Vo of a piezoelectric transformer 20. A drive voltage control device 15 controls a drive voltage Vs based on the electrostatic induction voltage Vs. A drive portion 17 supplies the controlled drive voltage Vd to the piezoelectric transformer 20, which transforms the supplied drive voltage Vd and supplies the voltage to a load 90 as the output voltage Vo. The voltage detection electrode 11 detects the electrostatic induction voltage Vs by the output voltage Vo and this operation is repeated. The output voltage Vo is detected indirectly by the voltage detection electrode 11 so that there is no need to use a resistor when detecting the output voltage Vo. Consequently, a current for detecting the output voltage Vo cannot be mixed with the output current Io, so that the output current Vo can be detected without deteriorating the control accuracy of the output current Io. COPYRIGHT: (C)2007,JPO&INPIT
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