Two-stage low-frequency square-wave-driven electronic ballast for HID lamps

This paper presents a novel two-stage low-frequency square-wave-driven electronic ballast for high-intensity-discharge (HID) lamps. The ballast is comprised of a PFC stage to achieve power factor correction and a low/high-frequency-driven half-bridge inverter to supply low-frequency square-wave sources to the lamp without causing acoustic resonance. The features of the proposed ballast are high power factor (≫0.99), cost-effectiveness, and lack of acoustic resonance. This paper also presents operational principles and experimental results for the proposed ballast for one 70W HID lamp operating at 200Hz switching frequency with 90V
rms
to 265V
rms
input utility-line voltage.