An Improved Topology for the Current Fed Parallel Resonant Half Bridge Circuits Used in Fluorescent Lamp Electronic Ballasts

Abstract

An improvement in the current fed parallel resonant half bridge (CFPRHB) circuits used in fluorescent lamp electronic ballasts is provided in this paper. The CFPRHB belongs to the self-oscillating family which includes the current fed push-pull and series resonant inverters, most of which are used in instant-start applications. However, many failure modes are related to the bypass capacitor according to an analysis of failed samples. In this paper, the operating functions of the existing topology in the steady state are analyzed and the main root cause of failure modes has been found. Comparisons between the two topologies are conducted in terms of the voltage stress of the bypass capacitor as well as the thermal and performance of the ballasts to verify the advantages of the proposed topology. It is found that the improved topology is capable of enhancing the reliability and reducing the cost of products without having a negative influence on the system performance.

Control Method for Phase-Shift Full-Bridge Center-Tapped Converters Using a Hybrid Fuzzy Sliding Mode Controller

“…The non-insulated converters for the LDC include the buck and buck-boost converter [7]. The insulated converters for the LDC include flyback, forward, push-pull, half-bridge, and full-bridge converter [8][9][10]. Among the insulated converters, the flyback, forward, and push-pull converter have disadvantages such as the large size of the transformer and the voltage stress of the switches.…”