Laptop Adaptor Using a Piezoelectric Transformer -Drive Circuit Development-

摘要

This paper describes incorporation of a piezoelectric transformer into a laptop computer adaptor in order to miniaturize the size and improve the energy utilization. Conventionally, electromagnetic transformer is used in the adaptor for generating the 45W output power. In this study, we show that a multilayer piezoelectric transformer rated 30W output power can satisfy the laptop specifications. The multilayer piezoelectric transformer prototype 27 mm in diameter and 4.7 mm in thickness, operated at 83 kHz under radial mode excitation was fabricated. The drive circuit was operated under near zero voltage switching condition for lowering switching loss. Consequently, the laptop adaptor was made with less than a half of its electromagnetic in volume.