Uniform Current Distribution in Driving Cold Cathode Fluorescent Lamps (CCFL) in Parallel

Cold cathode fluorescent lamps (CCFL) show complex characteristics, which make it difficult to drive them in parallel. In this paper, analysis of the lamp current distribution in parallel operation is presented in detail. The current balancing condition, under which the lamp currents are well balanced in the presence of the lamp voltage variation, is derived. The analysis results are verified from experiments with two 720 mm/4 mm CCFL's for 32-inch LCD TVs. Experimental results with eight CCFL's in parallel are also presented