An adaptive analog front end for a flexible PPG sensor patch with self-determined motion related DC drift removal

Rajeev Kumar Pandey, Paul C.-P. Chao*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Scopus citations

Abstract

This paper presents, a DC drift compensated (due to motion <1Hz), high sensing precision and wide dynamic range analog front end (AFE) for the organic type PPG sensor. The proposed AFE utilizes an auto-programmable trans-impedance amplifier (TIA) with the DC-current cancellation loop and a band pass filter to compensate the DC drift either due to motion or ambient light change. The prototype of the readout circuit is implemented in an integrated chip with an area of 3mm2 via the TSMC 180nm process. The experiment result shows that the designed readout can sense linearly from 1nA to maximum 40µA current, with a resultant dynamic range of 90dB and the measured input-referred noise is 0.256 nA/ √ Hz. The total measured power consumption of the readout circuit is 460µW, while the power consumption of the on-chip OLED driver is 1.8 mW. The obtained PPG signals from the wrist are subsequently processed with quality checking, and feature extraction. The measured accuracy and standard error for the heart rate estimation are 96%, and -0.12±5 beats/minute, respectively.

Original languageEnglish
Title of host publication2021 IEEE International Symposium on Circuits and Systems, ISCAS 2021 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781728192017
DOIs
StatePublished - May 2021
Event53rd IEEE International Symposium on Circuits and Systems, ISCAS 2021 - Daegu, Korea, Republic of
Duration: 22 May 202128 May 2021

Publication series

NameProceedings - IEEE International Symposium on Circuits and Systems
Volume2021-May
ISSN (Print)0271-4310

Conference

Conference53rd IEEE International Symposium on Circuits and Systems, ISCAS 2021
Country/TerritoryKorea, Republic of
CityDaegu
Period22/05/2128/05/21

Keywords

  • Filter
  • Flexible patch
  • Motion artifact rejection (MAR)
  • OLED
  • OPD
  • Photoplethysmography (PPG) Sensor

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