| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that it is difficult to stably control a power supply circuit having a piezoelectric transformer at a low voltage because it is easily influenced by a spurious frequency when a wide voltage range is required. <P>SOLUTION: The power supply unit is provided with a piezoelectric transformer 501, a drive circuit for driving the piezoelectric transformer 501, a control circuit 510 for controlling a drive frequency by the drive circuit, and a rectifying circuit for rectifying an output voltage of the piezoelectric transformer 501 and supplying the rectified voltage to a load. The reference voltage of the rectifying circuit is determined by a constant voltage element 521 connected in series to the ground level of the load. <P>COPYRIGHT: (C)2009,JPO&INPIT |
