Piezoelectric transformer converter with frequency control

An efficient piezoelectric transformer (PT) power converter with frequency control is presented. The optimum-designed reactance components are able to keep power efficiency high while controlling the output voltage for some load variation. An implemented PT power converter with frequency control achieves an efficiency higher than 75% at V/sub o/=5 V, I/sub o/=0.5-2 A, and switching frequency of around 2 MHz. Furthermore, a means to improve the voltage control characteristic over a wide range is also added.