A new control scheme of Class-E electronic ballast with low crest factor

In this paper, a new control scheme of Class-E inverter for reducing the crest factor of electronic ballasts for fluorescent lamps using pulse-frequency-modulation (PFM) is introduced. The lifetime of the lamps is guaranteed by decreasing the lamp crest factor and also voltage stress of the switch is significantly decreased by a new scheme although conventional Class-E inverter is used in this paper. The proposed PFM control scheme doesn´t used any auxiliary circuit. The proposed control strategy is executed by feeding back the input voltage, and the zero-voltage-switching (ZVS) is ensured by operating beyond resonant frequency. Therefore, the control principles of the proposed method are explained in detail and its validity is verified through several simulation and experimental results.