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HID (High Intensity Discharge) lamp has high efficiency, long service time, multiple types of light output, high color temperature, and some other advantages, which is a new generation of green energy-saving light source. HID lamp can connect to the grid and operate regularly only with ballast due to its negative resistance characteristic. Presently, the inductance ballast in use is low-PFC, large-volume, and low-efficiency. Hence, the dissertation studies on the electronic ballast which has higher PFC, higher efficiency, and intelligent.The paper studies on three-stage electronic ballast. To begin with, the operating principle of PFC Boost critical mode is analyzed and the formula is derived to study the PFC circuit. Then, the DC/DC topology is studied, and operating status of Buck converter in different mode is analyzed. And the DC/AC circuit is analyzed and the influence to the HID of full bridge dead time is analyzed. Last, the ignition circuit and two operation principles are studied.On the basis of the paper research, a 70W electronic ballast for HID is designed. Firstly, the parameters and control circuit of boost PFC circuit and is designed. Secondly, parameters and control circuit of the buck circuit is designed. Thirdly, drive circuit of inverter is designed. At last, the high-voltage trigger circuit is designed.Based on the parameter design in the paper, PCB board is made, and the hardware circuit and digital control program is debugged, which means the whole electronic ballast design is completed. In the paper, the designed electronic ballast is tested, and test waveforms and data shows that the performance of ballast is excellent, which satisfies the requirement of HID lamp.
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