A Simple Resonant Switched-Capacitor LED Driver Employed as a Fast Pulse-Based Transmitter for VLC Applications

This article presents a resonant switched-capacitor (RSC) dc–dc converter for visible light communication (VLC) applications operating as both high-efficiency power converter and fast-response data transmitter. By operating under soft switching, the topology allows for higher switching frequency and higher slew rate so that the VLC functionality can be embedded into the power stage without an auxiliary switch. In the literature, this additional switch has been presented as a viable implementation of on–off-keying (OOK) and variable pulse position modulation (VPPM) for data transmission yet, at the same time, is a major efficiency bottleneck for higher transmission rates due to its inherent hard-switching operation. This justifies new efforts in enabling pulse-based transmission (PBT) without this additional switch. A 10-W prototype was built to demonstrate such feasibility, operating at a switching frequency of 500 kHz, resulting in nominal efficiency of 85% during data transmission under the VPPM scheme, achieving up to 100 kb/s for various brightness levels, over a distance up to 1m.