A study on Driving of 35W(T5) fluorescent lamp by the electronic ballast using piezoelectric transformer

Recently, 35 W class Fluorescent lamps with 32 mm tube diameter are replaced with 32 W one with 26 mm in diameter to conserve lamp materials and to increase luminance efficiency. Moreover, 35, 28 and 14 W fluorescent lamps with 16 mm (T5) in diameter, which are nowadays developed, also may replace 32 W lamps again. Application of slim lamps, however, requires small sized electronic ballast to full fill the design philosophy of miniaturizing. However, the traditional magnetic ballasts operated at 50-60 Hz have been suffered from noticeable flicker, high loss, large crest factor and heavy weight. In this study, in order to solve these problems, a new type of electronic ballast, which is composed of rectifier, active power factor corrector, series resonant half bridge inverter and piezoelectric transformer, was proposed for driving T5 fluorescent lamp. Driving of piezoelectric transformer was carried out with input region for the ring electrode and output region for the dot electrode. A 35 W (T5) fluorescent lamp is successfully driven by the fabricated ballast with piezoelectric transformer. After driving the lamp using the proposed electronic ballast for 20 min, the input power factor and efficiency of ballast shown 0.95 and 86%, respectively, at operating frequency of 81 kHz. And also, the output power and temperature rise of piezoelectric transformer showed 35.07 W and 20.5 degC, respectively.