2.65 MHz Self-oscillating Complementary Electronic Ballast with Constant-lamp-current Control for Metal Halide Lamp

This paper presents the design and implementation of the 2.65 MHz self-oscillating complementary electronic ballast with a constant-lamp-current control for metal halide lamp. In order to avoid the inherent acoustic-resonance problem of metal halide lamps, the ballast\´s switching-frequency level was selected to be 2.65 MHz, which satisfies higher magnitudes of maximum EMI limitation at frequencies of between 2.5 MHz to 3.0 MHz, within the EMI/EMC frequency range "chimney," for RF lighting systems. With the constant-lamp-current control scheme, the lamp current can be regulated to be less dependent on the input AC voltage. Finally, a 20 W prototype ballast is implemented to demonstrate the ability to avoid the acoustic-resonance and to provide constant levels of lamp current