Burst-Mode Resonant LLC Converter for an LED Luminaire With Integrated Visible Light Communication for Smart Buildings

This study presents a digitally controlled LLC resonant dc-dc converter targeted to white LED luminaires in smart buildings. The module uses the LED array both for ambient lighting and for transmitting sensor data. Visible light communication is implemented with minimal incremental cost, by operating the LLC converter in burst mode, without causing any visible disturbance. The converter operates with a regulated average LED current, while the burst pulse timing is controlled to minimize the current disturbance and reduce the output capacitance. Variable pulse position modulation is used to modulate the data, while supporting a range of dimming settings. A digital demodulation scheme that supports variable frequency transmission is demonstrated. The 80 W, 340-400 to 23 V converter prototype has an efficiency of 95.1%. The bit error rate of the complete system is fully characterized versus distance and angle.