A Comparator‐Less ASK‐OOK Data Demodulator Circuit for Downlink Data Transfer Over Inductive Link

ABSTRACT In this paper, we propose a novel comparator‐less amplitude shift keying (ASK) demodulator circuit with an on‐off keying (OOK) encoding scheme. The proposed circuit can fully demodulate the data without requiring a bulky comparator circuit. The data is extracted by passing the sinusoidal ASK‐OOK signal through the input buffer circuit and sawtooth peak to time converter (SPTC) circuit with an inverter, followed by the output driver circuit. This circuit is designed for biomedical implants utilizing a single inductive coupled wireless power transfer (WPT) system, where data and power can be transferred simultaneously, eliminating the need for a dedicated inductive data link. A prototype circuit is designed and fabricated using 180‐nm CMOS technology with a compact core area of 1.08 mm 2 . The circuit achieves an energy efficiency of 33.6 pJ/bit at a data rate of 1 Mbps.