Dimmable LED driver with variable inductor based on a resonant switched-capacitor topology

This paper proposes a new 48 V DC-fed dimmable LED driver based on a Resonant Switched-Capacitor Topology (RSCT) where the analog-based dimming feature is accomplished by means of a variable inductor (VI). The proposed topology is based on the classic RSCT step-up double mode converter and it provides a simple and cost-effective solution while guaranteeing a wide dimming range. In order to implement an analog-based dimming the control of the dc current in the LED lamp is required. This technique proposes to replace the resonant inductor by a VI, which will control the rms value of the resonant current, and therefore the mean value of the LED lamp current. In order to evaluate the feasibility and performance of this method a 22 W LED lamp and driver prototypes were built. The most relevant experimental results are presented and briefly described.