Fluorescent Lamp Ballast based on a Class-E Resonant Inverter Using a Piezoelectric Transformer

The use of piezoelectric transformers in electronic ballasts has been widely discussed in recent literature. In most of the applications, the piezoelectric transformer substitutes all the resonant tank components of a half-bridge resonant inverter. However, designing the inverter to keep zero-voltage-switching in all the operating range is difficult due to the high input capacitance of piezoelectric transformers. The simplest topology that can be used to drive a piezoelectric transformer is the class-e inverter. In present paper, a simple procedure to achieve ZVS using the input inductor of the class-e inverter is described. The proposed procedure has been used to design a laboratory prototype based on a radial-mode piezoelectric transformer