Multilevel RF-PWM Switching-Mode Power Amplifier for Visible Light Communication

Abstract

Visible light communication (VLC) uses the light emitted by commercial high-brightness LEDs (HBLEDs) to transmit information. To vary the light intensity according to the communication signal to be transmitted, linear power amplifiers (LPAs) are typically used. However, their poor power efficiency poses a significant challenge for integration into a VLC driver, particularly at high power levels. To improve the efficiency of current VLC drivers, this work presents a novel switching-mode power amplifier (SMPA) based on a tuned three-level flying capacitor (FC) topology. The proposed FC-based SMPA, which is controlled by means of multilevel radiofrequency pulse-width modulation (RF-PWM) techniques, is able to reproduce passband modulation schemes with broader bandwidths in comparison to other conventional SMPAs. The idea has been validated with the transmission of a quadrature amplitude modulation (QAM) using a 160 W HB-LED load, achieving apeakefficiencyof98.3%andamaximumbitrate of 4 Mbps at a distance of 3 m.