| 摘要 |
<p>A method and an apparatus for controlling input-side frequency of a piezoelectric transformer are provided to adaptively change the control range of input-side frequency according to peripheral temperature change and the difference between objects. A phase instruction value generator(300) calculates the voltage difference between a reference output voltage desired to be output through a piezoelectric transformer and the actual output voltage of the piezoelectric transformer, and outputs a phase instruction value corresponding to the voltage difference. A limiting circuit(350) passes the phase instruction value within a predetermined range. A phase difference detecting unit(200) calculates the phase difference between the input and output voltages of the piezoelectric transformer. A voltage-controlled oscillator(500) supplies input-side frequency to the piezoelectric transformer. A phase compensator(400) controls the frequency of the voltage-controlled oscillator based on the difference between the phase instruction value and the phase difference.</p> |
