Contributions to low-cost, nonresonant electronic ballasts

The aim of this paper is to revisit the theme of non-resonant electronic ballasts focusing on a specific topology introduced in the last few years. Its complete mathematical analysis, which has not been fully explored in the past, and its practical implementation as a dc-fed electronic ballast unit is provided. The ballast here presented was successfully prototyped and is capable of pre-heating, igniting and driving two or more fluorescent light bulbs in series and has intrinsic protection against broken filaments and lamp absence. Furthermore, it relies solely on a single power switch and a relatively small-sized inductor per lamp, plus simple op-amp based control circuitry. An external protection circuitry is also presented in this paper, for protecting the power switch against lamp faulty conditions.