On the Use of Class D Switching-Mode Power Amplifiers in Visible Light Communication Transmitters

Abstract

Visible Light Communication (VLC) is a wireless communication technology that uses visible light to transmit information. The most extended implementation of a VLC transmitter employs a DC-DC power converter that biases the High-Brightness LEDs (HB-LEDs), and a Linear Power Amplifier (LPA) that reproduces the communication signal. Unfortunately, the power efficiency of LPAs is very low, thus reducing the overall system efficiency and requiring huge cooling systems to extract the heat. In this work, the use of Class D Switching-Mode Power Amplifiers (SMPAs) is explored in order to overcome that limitation. It is important to note that this SMPA is widely used for different applications, such as audio and RF power amplifiers. Therefore, there are a lot of versions of a Class D SMPA depending on the topology used for the implementation and the modulation strategy used to control the switches. Hence, this work aims to identify, adapt and explain in detail the best approach for implementing a Class D SMPA for VLC. In order to validate the proposed idea, a power-efficient VLC transmitter intended for short-range and low-speed applications was built and evaluated.

Design of broadband power amplifier based on loop-shaped filter matching structure

“…At present, the technologies to improve efficiency mainly include envelope tracking (ET) [1,2], envelope elimination and restoration (EER) [3,4], switch-type PAs, etc. ET and EER require peripheral circuits, so the design process is more complicated, while switch-type PAs such as class-E [5,6], class-F [7,8], and class-D [9,10] cannot maintain broadband due to their design characteristics. Continuous mode PA is one of the effective ways to expand its working bandwidth while ensuring high efficiency [11,12,13].…”