A high efficiency integrated step-down Cuk and flyback converter for LED power driver

Due to the enormous progress recently achieved in the technology of light emitting diodes (LEDs), they are expected to replace conventional lamps in automotive applications in the near future and incandescent, halogen and fluorescent lamps at least in some general illumination applications within a few years. Innovative driver circuits optimized with respect to functionality, efficiency, cost, size and reliability are an enabler for the successful introduction of new LED based lighting products. A low ripple and high efficiency single-stage power driver is proposed for LED lighting in this paper. The proposed single-stage power driver integrated a step-down Cuk rectifier for power-factor correction (PFC) with the isolated flyback converter for DC-DC power conversion. In the proposed single-stage step-down Cuk rectifier achieve low input ripple and output ripple and lower switch stress, and reduce the two energy conversion stages to improve the driver efficiency. The analysis of the proposed converter is presented and experimental results based on 0.75A, 30 W prototype are provided to demonstrate the performance of the proposed driver.