FSK Demodulation in Wireless Charging Technology

Abstract

Wireless charging is a technology that eliminates the need for physical wire connections to charge portable electronics like cell phones, earbuds, and accessories. The Wireless Power Consortium is an international group that supports wireless charging. In-band communication is used by the transmitter and receiver in wireless charging. AM modulation will be used by the receiver to communicate with the transmitter, and FSK modulation will be used by the transmitter to communicate with the receiver. Communication in wireless charging technology is half-duplex type.

            To decode the data that the transmitter transmits, the receiver must implement FSK Demodulation. Due to the extremely small time difference between the carrier and modulator signals, standard FSK demodulation techniques using PPL-based or Filter-based methods will not work. In the document, FSK demodulation method is developed which can decode the data. It uses a sampler to output a sampled signal that has been through a low pass filter after sampling the FSK signal. This is sent to a device that can detect frequency shifts, the frequency shift detector.