| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problems that an operation is not always performed at the maximum efficiency point because control is performed so that a phase difference between a voltage and a current applied to a primary side becomes zero, and it is hard to avoid the convergence to a spurious. <P>SOLUTION: An addition part adds an output from a phase difference detector for generating a control signal that reduces a phase difference between a voltage and a current applied to a primary side of a piezoelectric transformer, and an output from a phase offset generator. An output from the addition part is inputted to a voltage-controlled oscillator. In addition, when the output from the addition part deviates from a setting range, an input signal of the voltage-controlled oscillator is forcibly fixed. Thereby, an operation at the maximum efficiency point can be achieved, and the convergence to a spurious can be avoided. <P>COPYRIGHT: (C)2013,JPO&INPIT |
