| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that, the electromagnetic transformer (or the coil) of a constituent of a conventional piezoelectric transformer drive circuit generates a heat if a wire size is not thickened and not increased in size, resulting in remarkably deteriorating an efficiency, and reducing in thickness and size as a portable apparatus. <P>SOLUTION: By paying attention to that the AC adapter voltage of the portable apparatus is higher than the voltage of a battery, a voltage limiter circuit is disposed at a front stage, driven without power loss at a battery drive time, or an instantaneous current increase is suppressed at an AC adapter drive time. Thus, a low-cost small-sized and low height piezoelectric transformer drive circuit is provided. <P>COPYRIGHT: (C)2004,JPO |
