A CMOS Transimpedence Amplifier With Ambient Light Rejection for Visible Light Communication in Intelligent Transport Systems

A fully differential transimpedence amplifier (TIA) that serves as a receiver front-end for visible light communication (VLC) is proposed. The TIA incorporates an ambient light rejection circuit in the form of a floating active inductor (FAI) which can effectively bypass photocurrent (upto 50 mu A) and allows the subsequent transimpedence stage to only integrate the modulated photocurrent. This helps to avoid receiver saturation when exposed to excessive optical interference (i.e. large DC photocurrent) in outdoor environment of intelligent transport systems (ITS). Implemented in TSMC 0.18 mu m CMOS process, the proposed VLC receiver front-end consumes 220 mu A bias current and exhibit transimpedence gain of 98dB Omega. Our design is aimed for VLC based receivers in intelligent transport systems by enabling active tracking between VLC transmitter and receiver using the same degree of polarization of light.