Design of law frequency square wave electronic ballast for the ceramic MH lamp

Electronic ballast for the ceramic MH lamps is proposed. The ballast consists of active PFC, inverter, power control circuit and igniter. The lamp driving stage is a dual buck inverter which is used to drive lamps with a low-frequency square-wave voltage and current. The dual buck inverter switches are controlled by power control circuit to maintain the rated lamp power. It can not only dim the lamp but eliminate the acoustic resonance. The prototype of electronic ballast driving 250 W ceramic MH lamps was verified by experimental results.