Digitally Controlled Integrated Electronic Ballast with Dimming and Power Factor Correction Features

This paper presents a digitally controlled integrated electronic ballast with dimming and power factor correction features. The control circuit is based on a low-cost PIC16C71 microcontroller where the different strategies for energy saving have been implemented. The ballast is operating in closed loop achieving tight lamp current regulation through a digital Proportional-Integral algorithm. The integrated power stage is based on a frequency-controlled single-switch boost rectifier plus a half-bridge series resonant parallel loaded inverter sharing one power switch. The single-switch boost rectifier works in discontinuous inductor current mode with automatic power factor correction. Detailed analysis of the power stages and experimental results using 42-watt electronic ballast are presented.