| 摘要 |
PROBLEM TO BE SOLVED: To provide a constant-current power supply unit capable of obtaining a circuit which can keep an output current to a load at a prescribed value with high accuracy, and can control an oscillation frequency to a piezoelectric transformer with high accuracy that is not influenced by external factors, and achieving a simple constitution and cost reduction. SOLUTION: An AC voltage outputted from the piezoelectric transformer 4 is distributed by at least two resistors R13, 14, and a resistance pressure voltage dividing circuit 5 which steps down the AC voltage to be outputted is provided to return the AC voltage outputted by the resistance voltage dividing circuit 5 to an oscillation circuit 2 through a feedback circuit 9. Additionally, the oscillation circuit 2 generates an arbitrary oscillation frequency by using the AC voltage returned by the feedback circuit 9 as a control signal and outputs the frequency to the piezoelectric transformer 4. COPYRIGHT: (C)2008,JPO&INPIT
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