Single-switch electronic ballast with near-unity power factor and soft-switching characteristic

The design and analysis of a single-switch electronic ballast with near-unity power factor and soft-switching characteristic are presented. The ballast circuit is simple and has a small component count. The experimental results for an 80 W ballast show that it has a power factor higher than 0.99 and a total harmonic distortion of 12%. The operating frequency is between 20-40 kHz. The output power is adjustable and the circuit is reliable.