Taking advantage of the output voltage ripple of a two-phase buck converter to perform quadrature amplitude modulation for visible light communication

摘要

A DC-DC power converter based on a two-phase buck converter that performs Quadrature Amplitude Modulation (QAM) by using the first harmonic component of its output voltage ripple is studied in this work. The DC-DC power converter carries out both the illumination and the transmission functionalities of Visible Light Communication (VLC) transmitters. Control of both the amplitude and the phase of sinusoidal currents injected towards High-Brightness LEDs (HB-LEDs) enables the use of modulation schemes like QAM. This modulation scheme achieves higher spectral efficiency (i.e. greater number of bits per symbol transmitted) than previously proposed modulation schemes performed by DC-DC power converters for VLC. Moreover, the ratio between the bit rate achieved and the switching frequency of the DC-DC power converter presented in this paper is the highest obtained related so far.