Piezoelectric transformer for power converter operating at high frequency

This paper presents a new sort of multilayer piezoelectric ceramic transformer for switching regulation power supplies. This piezoelectric transformer operates in the second thickness resonant vibration mode. Accordingly its resonant frequency is higher than 1 MHz. Output power of our past work was low if the input and output parts of the transformer consisted of a single layer. In order to overcome this problem, this research suggests a new method, which is consisted of both input and output part of transformer have 2-layered piezoelectric ceramics. The size of transformer is 20 mm in width and length, and 1.4 mm in thickness, respectively. To design a high efficient switching circuit of the transformer, internal circuit parameters were measured, and then we´ve calculated a parameter of inductor and capacitor to design a driving circuit. We´ve used a MOSFET and it´s gate driver circuit modified a clap oscillator circuit as the primary switching circuit.