A two-stage electronic ballast for 400-W metal halide lamp with frequency modulation control is presented in this thesis. This electronic ballast consists of a boost PFC stage, SRPL half bridge inverter stage, frequency modulation control circuit and constant power control circuit with digital microcontroller PIC12F675. The boost PFC circuit is operating in continuous conduction mode to achieve high power factor, and the SPRL half bridge inverter driving, supply the HID lamp with a high frequency sinusoidal wave current by frequency modulation to avoid acoustic resonance. Finally, a laboratory prototype of 400 W electronic ballast for metal halide lamp with 90∼264 Vac universal input voltage is implemented. The measured results show that the proposed ballast can be applied for various HID lamps with low lamp power variation. The maximum power factor is 0.99 and the maximum efficiency of the ballast is 94.8%.