Performance evaluation of dimmable electronic ballast based on frequency and bus voltage variation

This paper presents a performance comparison between two dimming methods for an electronic ballast that feeds a T5 HE 28 W fluorescent lamps. An IR21592 dedicated integrated circuit is employed in the half-bridge inverter stage with a LCC resonant filter. A PFC stage is implemented with a Single-Ended Primary Inductance Converter with constant output voltage or variable output voltage according to the dimming method. A standard circuit IR21592 is employed to dim the lamp based on a standard method of inverter frequency variation with a constant PFC output voltage. A modified operation mode of IR21592 is employed also to dim the fluorescent lamp through a PFC stage output voltage and inverter frequency variation dimming method. For both methods experimental results are presented in order to make a comparison and to evaluate the general performance.