A dimmable LED driver for visible light communication (VLC) based on LLC resonant DC-DC converter operating in burst mode

The main focus of this work is the integration of the communication and power management functions of a 80W smart LED module. The luminair provides high-efficiency programmable ambient lighting and can also act as a networked sensor node to gather a variety of local measurements, which leads to improved safety, comfort and efficiency in future lighting systems. A dimmable LED driver based on the LLC resonant dc-dc converter topology is proposed to implement an emerging communication scheme, Visible Light Communication (VLC). VLC capitalizes on the high switching-speed of LEDs and offers several compelling advantages over conventional RF and wired communication schemes. The digitally controlled LLC converter operates in constant-current burst mode, where the burst is sequenced to independently control the dimming and transmission the data using the Variable Pulse Position Modulation (VPPM) protocol. A receiver circuit is designed to demodulate and decode the visible light signal. The 50 kb/s system is successfully demonstrated on a 308 LED Luminair with a digitally controlled LLC dc-dc converter.