Design and Implementation of a Single-Stage Acoustic-Resonance-Free HID Lamp Ballast With PFC

High-intensity-discharge (HID) lamps are widely utilized in a variety of lighting circumstances that need high luminance. This paper proposes a single-stage electronic ballast for HID lamps; the ballast offers power factor correction and is acoustic resonance free. The presented HID lamp ballast integrates a discontinuous-conduction-mode (DCM)-operated bridgeless power factor correction (PFC) converter for shaping the input utility-line current with a high-frequency (36 kHz)/low-frequency (60 Hz) square-wave-driven half-bridge inverter for supplying low-frequency (60 Hz) square-wave sources to the HID lamp. The features of the proposed ballast are high power factor, low total harmonic distortion (THD) of the input current, cost effectiveness, and that it avoids acoustic resonance. The operational modes, key design guidelines, and a design example are included. A 70 W prototype HID lamp ballast circuit operating with 110 V-rms input utility-line voltage has been implemented and testified. The functionalities of the presented ballast are demonstrated by satisfactorily experimental results with a maximum efficiency of 90.8%, a maximum power factor of 0.998, and a minimum current THD of 11.13%.