Dimmable single-stage SEPIC-Ćuk converter for LED lighting with reduced storage capacitor

This paper presents an analysis and design of a Light Emitting Diode (LED) driver aiming to substitute the electrolytic capacitors. Considering the low lifetime of electrolytic capacitors compared to LEDs, this topology aims for reducing the storage capacitance and replaces it by a longer lifetime capacitor, increasing the overall system life span. This reduction is based on designing a control dynamic with a compromise between the input current distortion and the output current ripple. The power factor correction (PFC) stage is based on a Single Ended Primary Inductance Converter (SEPIC) because of its intrinsic low input current distortion characteristic making it possible to eliminate the electromagnetic interference (EMI) filter. The power control (PC) stage is performed by a Ćuk converter using its output current source behavior in Continuous Conduction Mode (CCM), suitable for LED application. Furthermore a dimming strategy is also proposed and implemented by an LED parallel active switch.