CMOS Adaptive Optical Wireless Receiver for Ultra-Low-Power IoT Applications

An ultra-low-power adaptive optical wireless receiver comprising integrated photodiodes is presented. The design benefits from a new technique to achieve the modulated input data using a charge pump circuit in a closed-loop connection with a comparator. This method can automatically acquire a reference voltage for comparison and compensate comparator's offset errors and DC-level illumination changes. Electronic components and photodiodes are designed in a 0.18 μm Triple-well CMOS technology. Measured waveforms are presented for a pseudo-random stream input data, with a minimum 50 μs pulse width. The receiver's power consumption is 11 pJ/bit for a 20 kb/s data rate and a 0.9 V supply voltage. The proposed design's light beam communication, reduced power consumption, and small area make it suitable for ultra-low-power IoT applications.