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.