Improvement on component stresses of single-stage electronic ballasts

This paper presents an improvement on component stresses of single-stage electronic ballasts derived with synchronous switch technique (SST). Based on the SST, the derivation of a single-stage inverter (SSI) used for realizing the ballasts is then addressed. The SSI can achieve both high power factor and ballasting function. During lamp start-up transition, power imbalance may exist between the power factor correction semi-stage and the ballast semi-stage. This imbalance usually results in a high DC-link voltage which, in turn, impairs the switching devices. Investigation of component stresses due to this imbalance from start-up transition through steady state operation is conducted. Control strategies for reducing component stresses and hot resistance detection circuits for minimizing electrode sputtering are therefore proposed. Hardware measurements are presented to verify the theoretical discussions.