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A 2.3-5.7 μW Tri-Modal Self-Adaptive Photoplethysmography Sensor Interface IC for Heart Rate, SpO 2 , and Pulse Transit Time Co-Monitoring.
- Source :
-
IEEE transactions on biomedical circuits and systems [IEEE Trans Biomed Circuits Syst] 2024 Jun; Vol. 18 (3), pp. 564-579. Date of Electronic Publication: 2024 May 28. - Publication Year :
- 2024
-
Abstract
- This paper presents a tri-modal self-adaptive photoplethysmography (PPG) sensor interface IC for concurrently monitoring heart rate, SpO <subscript>2</subscript> , and pulse transit time, which is a critical intermediate parameter to derive blood pressure. By implementing a highly-reconfigurable analog front-end (AFE) architecture, flexible signal chain timing control, and flexible dual-LED drivers, this sensor interface provides wide operating space to support various PPG-sensing use cases. A heart-beat-locked-loop (HBLL) scheme is further extended to achieve time-multiplexed dual-input pulse transit time extraction based on two PPG sensors placed at fingertip and chest. A self-adaptive calibration scheme is proposed to automatically match the chip's operating point with the current use case, guaranteeing a sufficient signal-to-noise ratio for the user while consuming minimum system power. This paper proposes a DC offset cancellation (DCOC) approach comprised by a logarithmic transimpedance amplifier and an 8-bit SAR ADC, achieving a measured 38 nA residue error and 8.84 μA maximum input current. Fabricated in a 65nm CMOS process, the proposed tri-modal PPG sensor interface consumes 2.3-5.7 μW AFE power and 1.52 mm <superscript>2</superscript> die area with 102dB (SpO <subscript>2</subscript> mode), 110-116 dB (HR & PTT mode) dynamic range. A SpO <subscript>2</subscript> test case and a HR & PTT test case are both demonstrated in the paper, achieving 18.9 μW and 43.7 μW system power, respectively.
- Subjects :
- Humans
Equipment Design
Monitoring, Physiologic instrumentation
Monitoring, Physiologic methods
Signal-To-Noise Ratio
Algorithms
Photoplethysmography instrumentation
Photoplethysmography methods
Heart Rate physiology
Signal Processing, Computer-Assisted instrumentation
Pulse Wave Analysis instrumentation
Pulse Wave Analysis methods
Subjects
Details
- Language :
- English
- ISSN :
- 1940-9990
- Volume :
- 18
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- IEEE transactions on biomedical circuits and systems
- Publication Type :
- Academic Journal
- Accession number :
- 38289849
- Full Text :
- https://doi.org/10.1109/TBCAS.2024.3360140