Single-Stage Offline SEPIC Converter with Power Factor Correction to Drive High Brightness LEDs

An interleaved SEPIC converter with LED current dimmable and input power factor correction is proposed as a high performance driver for the high brightness white LEDs. The converter is controlled with voltage mode PWM and run in discontinuous conduction mode so that the inductor current follows the rectified input voltage. The critical design constraints and equations for both the power stage and control loop are highlighted and detailed. A practical evaluation board with 110 V input and 60 V, 700 mA output is developed to verify the proposed design. The proposed converter can be used to drive a wide number of high brightness LEDs for industrial or commercial lighting applications.