A wide-input-range low-power ASK demodulator for wireless data transmission in retinal prosthesis

In biomedical implantable applications, ASK (Amplitude Shift Keying) modulation over an inductive link is often used to transmit data wirelessly. Due to the relative movements of coils, the received data signal can vary in a wide range, which makes the demodulation circuit design a challenge. In this work a wide-input-range low-power ASK demodulator is proposed. The design is implemented in X-FAB 0.35um CMOS process. The demodulator can work with an ASK input voltage swing from 0.05V-6V and a modulation index swing from 1.1%-100% at the carrier frequency of 13.56MHz and data rate of 700kbps. The whole circuit consumes an average power of 76.5uW.