A Low-Size Multi-Power-Level Single-Transistor Ballast for Low Pressure Fluorescent Lamps, Using a Piezoelectric Transformer

摘要

A 5 to 18 Watts multi-power level demonstrator with a Transoner-type Piezoelectric Transformer (PT) has been built in class-E topology to show the full functionality of a low-size low-cost instant start ballast for fluorescent lamps. Zero-voltage switching was achieved for different output power levels (different tubes), at nominal input voltage of 230V AC, including tolerances, using one and the same PT sample and ballast circuit. The PT was 8mm thick, and had a diameter of 19 mm. The used switch, a 1200V Fieldstop-IGBT, 1 A-type, shows losses of 716 mW for 16.8 Watts output power, at a frequenciy of 119 kHz. The converter efficiency (without rectifiers) has been accordingly 89.5%.