A Simple Electronic Ballast to Supply HID Lamps

This paper presents an electronic ballast based on chopper to supply a 70W high intensity discharge (HID) lamp. The ballast consists on a bipolar buck chopper operating in continuous conduction mode (CCM) and an igniter circuit. It works with a switching frequency of 33 kHz and supplies the lamp in the mains frequency. The igniter circuit provides the necessary high voltage for the lamp's startup initial procedure. The goal is to supply the lamp from 220V plusmn 20% mains with a reduced number of components, decreasing the system final cost [14] without compromising the reliability and the lifetime. It is controlled by an 8 bits microcontroller, thus contributing to reduction in the number of parts. Some experimental results are presented to validate the proposed ballast, and its behavior shows it is a good choice to avoid the effects of acoustic resonance phenomenon.