A study of sinusoidal-excited wall charge behavior in EEFL by parallel-loaded series resonance

Abstract

This paper reveals the discharging behavior of the wall charge in an external-electrode fluorescent lamp (EEFL) in terms of the lamp current in differential response to lamp voltage. A sinusoidal lamp current, instead of pulsated lamp current, enriches the wall charge exchange in EEFL, which can make soft luminance as well as prevent twinkling light that may damage the lamp. A well-known parallel-loaded series-resonant inverter (PL-SRI), instead of SRI, is well suited to the characteristic of EEFL so that it can enrich enough energy for wall charge exchange. A design approach mixing theoretical with experimental means validates the characteristic matching between EEFL and PL-SRI in practice. Experiments verify that the EEFL is almost a pure capacitor as a predicted model. A comparison of wall charge behaviors with those that are excited by a square wave is examined.