On the Performance and Power Consumption of Bias-T Based Drivers for High Speed VLC

LED lamps have become the predominant technology for lighting thanks to their low power consumption. Recently, the joint use of these devices for lighting and data transmission has aroused interest in the research community as a future green communication technology. During this time, many of the advances developed in this area have been demonstrated with experimental setups using LED drivers based on bias-T, thanks to their ease to combine signal modulation and LED bias. This article discusses the impact of the output impedance of the bias-T driver and the driver-LED connection parasitics on the performance and energy efficiency of the VLC system. It is concluded that the output impedance of the driver not only affects energy efficiency but also modifies the frequency response and, therefore, the LED's capacity to be modulated. A low output impedance driver is shown to offer a substantial improvement in the energy efficiency of the VLC driver.