A Low-Power, Auto-DC-Suppressed Photoplethysmography Readout System with Differential Current Mirrors and Wide Common-Mode Input Range Successive Approximation Register Analog-to-Digital Converter

This paper presents a low-power photoplethysmography (PPG) readout system designed for wearable health monitoring. The system employs a differential current mirror (DCM) to convert single-ended PPG currents into differential voltages, inherently suppressing DC components. A wide common-mode input ra...

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Main Authors: Chanyoung Son, Seok-Tae Koh, Hyuntak Jeon
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Micromachines
Subjects:
Online Access:https://www.mdpi.com/2072-666X/16/4/398
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author Chanyoung Son
Seok-Tae Koh
Hyuntak Jeon
author_facet Chanyoung Son
Seok-Tae Koh
Hyuntak Jeon
author_sort Chanyoung Son
collection DOAJ
description This paper presents a low-power photoplethysmography (PPG) readout system designed for wearable health monitoring. The system employs a differential current mirror (DCM) to convert single-ended PPG currents into differential voltages, inherently suppressing DC components. A wide common-mode input range (WCMIR) SAR ADC processes the differential signals, ensuring accurate analog-to-digital conversion. The DCM eliminates the need for DC cancelation loops, simplifying the design and reducing power consumption. Implemented in a 0.18 µm CMOS process, the system occupies only 0.30 mm<sup>2</sup>, making it suitable for multi-channel applications. The system achieves over 60 dB DC dynamic range and consumes only 9.6 µW, demonstrating its efficiency for portable devices. The simulation results validate its ability to process PPG signals across various conditions, offering a scalable solution for advanced biomedical sensing platforms.
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publishDate 2025-03-01
publisher MDPI AG
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spelling doaj-art-9b3479f7cd264dcaaeba7d20832fa2e82025-08-20T02:18:04ZengMDPI AGMicromachines2072-666X2025-03-0116439810.3390/mi16040398A Low-Power, Auto-DC-Suppressed Photoplethysmography Readout System with Differential Current Mirrors and Wide Common-Mode Input Range Successive Approximation Register Analog-to-Digital ConverterChanyoung Son0Seok-Tae Koh1Hyuntak Jeon2School of Semiconductor Engineering, Chungbuk National University (CBNU), Cheongju 28644, Republic of KoreaSchool of Electrical Engineering, Chungbuk National University (CBNU), Cheongju 28644, Republic of KoreaSchool of Semiconductor Engineering, Chungbuk National University (CBNU), Cheongju 28644, Republic of KoreaThis paper presents a low-power photoplethysmography (PPG) readout system designed for wearable health monitoring. The system employs a differential current mirror (DCM) to convert single-ended PPG currents into differential voltages, inherently suppressing DC components. A wide common-mode input range (WCMIR) SAR ADC processes the differential signals, ensuring accurate analog-to-digital conversion. The DCM eliminates the need for DC cancelation loops, simplifying the design and reducing power consumption. Implemented in a 0.18 µm CMOS process, the system occupies only 0.30 mm<sup>2</sup>, making it suitable for multi-channel applications. The system achieves over 60 dB DC dynamic range and consumes only 9.6 µW, demonstrating its efficiency for portable devices. The simulation results validate its ability to process PPG signals across various conditions, offering a scalable solution for advanced biomedical sensing platforms.https://www.mdpi.com/2072-666X/16/4/398PPG (photoplethysmography)readout ICs (ROICs)differential current mirror (DCM)successive approximation register (SAR)analog-to-digital converter (ADC)
spellingShingle Chanyoung Son
Seok-Tae Koh
Hyuntak Jeon
A Low-Power, Auto-DC-Suppressed Photoplethysmography Readout System with Differential Current Mirrors and Wide Common-Mode Input Range Successive Approximation Register Analog-to-Digital Converter
Micromachines
PPG (photoplethysmography)
readout ICs (ROICs)
differential current mirror (DCM)
successive approximation register (SAR)
analog-to-digital converter (ADC)
title A Low-Power, Auto-DC-Suppressed Photoplethysmography Readout System with Differential Current Mirrors and Wide Common-Mode Input Range Successive Approximation Register Analog-to-Digital Converter
title_full A Low-Power, Auto-DC-Suppressed Photoplethysmography Readout System with Differential Current Mirrors and Wide Common-Mode Input Range Successive Approximation Register Analog-to-Digital Converter
title_fullStr A Low-Power, Auto-DC-Suppressed Photoplethysmography Readout System with Differential Current Mirrors and Wide Common-Mode Input Range Successive Approximation Register Analog-to-Digital Converter
title_full_unstemmed A Low-Power, Auto-DC-Suppressed Photoplethysmography Readout System with Differential Current Mirrors and Wide Common-Mode Input Range Successive Approximation Register Analog-to-Digital Converter
title_short A Low-Power, Auto-DC-Suppressed Photoplethysmography Readout System with Differential Current Mirrors and Wide Common-Mode Input Range Successive Approximation Register Analog-to-Digital Converter
title_sort low power auto dc suppressed photoplethysmography readout system with differential current mirrors and wide common mode input range successive approximation register analog to digital converter
topic PPG (photoplethysmography)
readout ICs (ROICs)
differential current mirror (DCM)
successive approximation register (SAR)
analog-to-digital converter (ADC)
url https://www.mdpi.com/2072-666X/16/4/398
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