A CMOS Switched Capacitor Filter Based Potentiometric Readout Circuit for pH Sensing System
This work presents a potentiometric readout circuit for a pH-sensing system in an oral healthcare device. For in vivo applications, noise, area, and power consumption of the readout electronics play critical roles. While CMOS amplifiers are commonly used in readout circuits for these applications, t...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
|
| Series: | Journal of Low Power Electronics and Applications |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2079-9268/15/1/3 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850090639825305600 |
|---|---|
| author | Shanthala Lakshminarayana Revathy Perumalsamy Chenyun Pan Sungyong Jung Hoon-Ju Chung Hyusim Park |
| author_facet | Shanthala Lakshminarayana Revathy Perumalsamy Chenyun Pan Sungyong Jung Hoon-Ju Chung Hyusim Park |
| author_sort | Shanthala Lakshminarayana |
| collection | DOAJ |
| description | This work presents a potentiometric readout circuit for a pH-sensing system in an oral healthcare device. For in vivo applications, noise, area, and power consumption of the readout electronics play critical roles. While CMOS amplifiers are commonly used in readout circuits for these applications, their applicability is limited due to non-deterministic noises such as flicker and thermal noise. To address these challenges, the Correlated Double Sampler (CDS) topology is widely employed as a sampled-data circuit for potentiometric readout, effectively eliminating DC offset and drift, thereby reducing overall noise. Therefore, this work introduces a novel potentiometric readout circuit realized with CDS and a switched-capacitor-based low-pass filter (SC-LPF) to enhance the noise characteristic of overall circuit. The proposed readout circuit is implemented in an integrated circuit using 0.18 µm CMOS process, which occupies an area of 990 µm × 216 µm. To validate the circuit performances, simulations were conducted with a 5 pF load and a 1 MHz input clock. The readout circuit operates with a supply voltage range ±1.65 V and linearly reproduces the pH sensor output of ±1.5 V. Noise measured with a 1 MHz sampling clock shows 0.683 µ<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>V</mi></mrow><mrow><mi>r</mi><mi>m</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula>, with a power consumption of 124.1 µW. |
| format | Article |
| id | doaj-art-7011d8df840a4a2c805d54c86b4e0d5c |
| institution | DOAJ |
| issn | 2079-9268 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Low Power Electronics and Applications |
| spelling | doaj-art-7011d8df840a4a2c805d54c86b4e0d5c2025-08-20T02:42:31ZengMDPI AGJournal of Low Power Electronics and Applications2079-92682025-01-01151310.3390/jlpea15010003A CMOS Switched Capacitor Filter Based Potentiometric Readout Circuit for pH Sensing SystemShanthala Lakshminarayana0Revathy Perumalsamy1Chenyun Pan2Sungyong Jung3Hoon-Ju Chung4Hyusim Park5Department of Electrical Engineering, University of Texas at Arlington, Arlington, TX 76019, USASr. Staff ATE Engineer, Movandi, CA 92618, USADepartment of Electrical Engineering, University of Texas at Arlington, Arlington, TX 76019, USADepartment of Electrical & Computer Engineering, South Dakota State University, Brookings, SD 57007, USASchool of Electronic Engineering, Kumoh National Institute of Technology, Gumi 39177, Republic of KoreaDepartment of Electrical Engineering, University of North Texas, Dallas, TX 75241, USAThis work presents a potentiometric readout circuit for a pH-sensing system in an oral healthcare device. For in vivo applications, noise, area, and power consumption of the readout electronics play critical roles. While CMOS amplifiers are commonly used in readout circuits for these applications, their applicability is limited due to non-deterministic noises such as flicker and thermal noise. To address these challenges, the Correlated Double Sampler (CDS) topology is widely employed as a sampled-data circuit for potentiometric readout, effectively eliminating DC offset and drift, thereby reducing overall noise. Therefore, this work introduces a novel potentiometric readout circuit realized with CDS and a switched-capacitor-based low-pass filter (SC-LPF) to enhance the noise characteristic of overall circuit. The proposed readout circuit is implemented in an integrated circuit using 0.18 µm CMOS process, which occupies an area of 990 µm × 216 µm. To validate the circuit performances, simulations were conducted with a 5 pF load and a 1 MHz input clock. The readout circuit operates with a supply voltage range ±1.65 V and linearly reproduces the pH sensor output of ±1.5 V. Noise measured with a 1 MHz sampling clock shows 0.683 µ<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>V</mi></mrow><mrow><mi>r</mi><mi>m</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula>, with a power consumption of 124.1 µW.https://www.mdpi.com/2079-9268/15/1/3CDSSC-LPFpotentiometric readoutCMOSpH sensing |
| spellingShingle | Shanthala Lakshminarayana Revathy Perumalsamy Chenyun Pan Sungyong Jung Hoon-Ju Chung Hyusim Park A CMOS Switched Capacitor Filter Based Potentiometric Readout Circuit for pH Sensing System Journal of Low Power Electronics and Applications CDS SC-LPF potentiometric readout CMOS pH sensing |
| title | A CMOS Switched Capacitor Filter Based Potentiometric Readout Circuit for pH Sensing System |
| title_full | A CMOS Switched Capacitor Filter Based Potentiometric Readout Circuit for pH Sensing System |
| title_fullStr | A CMOS Switched Capacitor Filter Based Potentiometric Readout Circuit for pH Sensing System |
| title_full_unstemmed | A CMOS Switched Capacitor Filter Based Potentiometric Readout Circuit for pH Sensing System |
| title_short | A CMOS Switched Capacitor Filter Based Potentiometric Readout Circuit for pH Sensing System |
| title_sort | cmos switched capacitor filter based potentiometric readout circuit for ph sensing system |
| topic | CDS SC-LPF potentiometric readout CMOS pH sensing |
| url | https://www.mdpi.com/2079-9268/15/1/3 |
| work_keys_str_mv | AT shanthalalakshminarayana acmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT revathyperumalsamy acmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT chenyunpan acmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT sungyongjung acmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT hoonjuchung acmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT hyusimpark acmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT shanthalalakshminarayana cmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT revathyperumalsamy cmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT chenyunpan cmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT sungyongjung cmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT hoonjuchung cmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem AT hyusimpark cmosswitchedcapacitorfilterbasedpotentiometricreadoutcircuitforphsensingsystem |