A Fully Digital ASK Demodulator With Digital Calibration for Bioimplantable Devices

A new fully digital high-efficiency ASK demodulator for detecting data via inductive link is proposed. The proposed demodulator does not use any passive component and is compatible with standard CMOS digital technology. The modulation index, modulation rate, and power consumption of the proposed structure are <;4%, 100%, and 118.2 μW, respectively, at the carrier frequency of 13.56 MHz. Design issues of the demodulator are discussed in detail. A calibration technique is also proposed for the demodulator which compensates the impact of PVT variations as well as coil displacements in case it is used in an inductive link data and power transfer system. The designed circuit is implemented in the 0.18-μm CMOS technology.