Self-Oscillating Full-Bridge Electronic Ballast with Constant-Lamp-Current Control and No-Lamp-Protection Circuit

This paper presents the self-oscillating full-bridge electronic ballast with constant-lamp-current control and no-lamp-protection circuit for use in fluorescent lamps. The proposed ballast resolves the two inherent issues related to the self-oscillating full-bridge electronic ballast. The first of these inherent problems is that the lamp current varies according to the input AC voltage to causes different levels of brightness of the lamp. Secondly, once the lamp load is removed or broken, the ballast continuously attempts to generate an abnormally excessive voltage and current, which results in failure of the components in the ballast. Integrating the constant-lamp-current control and the proposed no-lamp-protection circuit into the self-oscillating full-bridge electronic ballast resolves the ballast´s issues of unstable brightness and failure of the components during no-lamp conditions. Finally, a 38 W self-oscillating full-bridge electronic ballast with constant-lamp-current control and no-lamp-protection circuit for use in fluorescent lamps is designed and implemented to demonstrate the feasibility and performance of the proposed electronic ballast.