Magnetic dimming of electronic ballasts

Abstract

A new control method for electronic ballasts based on magnetic regulators is presented. The proposed method allows starting and dimming the lamp at constant frequency by adjusting the inductance of the resonant tank. The main advantages are inherent galvanic isolated control, more linear control characteristics, lower EMI, and high efficiency in the whole dimming range. Analysis and experimental results from a 36 W linear fluorescent lamp prototype are presented.