Design of an LED Sink Driver Using a Switched-Inductor and Switched-Capacitor Buck-Boost Converter with High Voltage Gains

A novel light emitting diode (LED) sink driver using a switched-inductor and switched capacitor (SISC) buck-boost converter is proposed in this paper. The proposed LED driver can achieve a high voltage gain by cascading the SI buck-boost block and the SC doubler block with a flying capacitor. The proposed negative SISC topology can provide not only high voltage gain but also flexible controllability of LED currents. The performance of the proposed SISC buck-boost converter was clarified by simulation program with integrated circuit emphasis (SPICE) simulations. In the performed simulations, the proposed SISC buck-boost converter can improve power efficiency about 6% from the conventional hybrid buck-boost converter when the duty factor D is 0.5 and the output power is 500mW. Furthermore, the feasibility of the proposed SISC topology was confirmed by breadboard experiments.