Low-power non-coherent data and power recovery circuit for implantable biomedical devices

In this paper, we present a low-power non-coherent amplitude shift keying (ASK) and phase shift keying (PSK) demodulators with inductive power self-recovery system, and the data-clock recovery circuit for implantable biomedical devices. Both circuits use different coupling factors k from 0.1 to 0.5 in ASK and 0.5 in PSK for inductive link The recovered power regulator that consists of a beta multiplier reference (BMR) with band-gap uses the bridge rectifier output as an unregulated DC input, and produces from 1.73 to 1.8 V regulated output for the demodulator with 2 MHz carrier. The PSK demodulator uses a new demodulation method that uses signals from two differential comparators with low-pass pre-filtered (LPPF) and high-pass pre-filtered (HPPF) outputs for detecting phase changing edges to recover data and clock signals. The full wave detecting signals are used as differential inputs in LPPF comparator of the ASK demodulator. The results of the demodulators with the self-power supply show up to less than 62 μW and 115 μW power consumption in ASK and PSK at 1 Mbps data transfer rate.