A Dimmable Offline LED Driver With OOK-M-FSK Modulation for VLC Applications

This paper proposes a visible light communication (VLC) system consisting of a single-stage buck- boost power factor correction converter operating in the discontinuous conduction mode with dimming capability. Additionally, this paper proposes the ON-OFF M-frequency shift keying modulation for the VLC system. This modulation allows for the transmission of more than a single bit for each switching period without affecting the dimming characteristics of the light-emitting diode luminaire. The design of the whole system is discussed in detail, including both transmitter and receiver modules. A 20-W laboratory prototype was built in order to verify the proposed modulation scheme. The experimental evaluation showed a good performance of the transmitter, which was able to perform simultaneously the desired functions, namely power factor correction, dimming, and data transmission. The receiver also achieved the desired performance with a low bit error rate (BER). The results showed that the proposed system was able to transfer data between emitter and receiver with a bit rate of 1.11 Mb/s at a frequency of up to 375 kHz over a distance of 10 m, and with a BER lower than 10
^-3
under the influence of external lighting sources with illuminance levels up to 500 lx.