Comparator-less ASK-PWM CDR Circuit for Forward Data Communication Over A Single Channel Wireless Power and Data Transfer System

In this work, a new clock and data recovery (CDR) scheme is proposed for amplitude shift keying (ASK) with pulse width modulation (PWM) encoding. Such a technique can fully recover the clock as well as the encoded data without the need for any comparator. The clock is recovered by passing the ASK-PWM encoded data to the frequency divider and frequency multiplier. Then, the data sampler can recover the data by sampling the ASK-PWM modulated data using a delayed version of the recovered clock with no additional processing. This technique is intended for a data transfer system over an inductively coupled wireless power transfer system (WPT) system for biomedical implants where the data will modulate the power carrier without the need for a dedicated data channel. A prototype example implementation of the CDR scheme on a 180 nm Complementary-Metal-Oxide-Semiconductor (CMOS) technology with a data rate of 2 Mbps is provided as a proof-of-concept. This CDR prototype has an area of 8000 mu m(2) and consumes a power of 129 microwatts from a 1.4 Voltage dc supply.