A Novel Direct Digitizer for Leaky Differential Capacitive Sensors Using Phase Sensitive Integration

Muhamed Jamshir, M; Vijayakumar, S; Das, S; Thiyagarajan, K; Kodagoda, S

A Novel Direct Digitizer for Leaky Differential Capacitive Sensors Using Phase Sensitive Integration

Muhamed Jamshir, M Vijayakumar, S Das, S Thiyagarajan, K

Kodagoda, S

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Publisher:: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Publication Type:: Journal Article
Citation:: IEEE Sensors Letters, 2024, 8, (2), pp. 1-4
Issue Date:: 2024-02-01

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Field	Value	Language
dc.contributor.author	Muhamed Jamshir, M
dc.contributor.author	Vijayakumar, S
dc.contributor.author	Das, S
dc.contributor.author	Thiyagarajan, K https://orcid.org/0000-0002-4044-1711
dc.contributor.author	Kodagoda, S https://orcid.org/0000-0001-5175-9138
dc.date.accessioned	2024-08-07T04:44:56Z
dc.date.available	2024-08-07T04:44:56Z
dc.date.issued	2024-02-01
dc.identifier.citation	IEEE Sensors Letters, 2024, 8, (2), pp. 1-4
dc.identifier.issn	2475-1472
dc.identifier.issn	2475-1472
dc.identifier.uri	http://hdl.handle.net/10453/180227
dc.description.abstract	A novel capacitance to digital converter (CDC), which estimates the capa-citance of a leaky differential capacitive sensor (DCS) based on phase sensitive integration (PSI) is presented in this letter. Various methods to measure the capacitance of a leaky capacitive sensor exist, but all these methods apply to single-element capacitive sensor. Most of the techniques, which measure capacitance of a DCS are sensitive to leakage resistance of the sensor. The proposed CDC works with alternating current excitation and employs PSI along with dual slope operation to estimate differential capacitance independent of the leakage resistance. In addition, the proposed CDC is insensitive to the stray capacitance (due to sensor structure or connecting cables) seen at the sensor terminals. Even though the measurand varies in a linear or nonlinear fashion with respect to sensor characterestics, the ratiometric output of the proposed CDC ensures that the output is linear with respect to the measurand. The prototype of CDC is tested for a wide differential range of ± 220 pF with a nominal value of 400 pF and worst case full scale (F.S) nonlinearity error of < 0.17% is observed. The prototype of CDC is tested for leakage resistance varying from 10 M Ω to 50 k Ω and worst case error of 1.1% is observed. The prototype of CDC is also tested for stray capacitance, varying from 10 to 200 pF and worst case error observed is 0.39%. Thus, the proposed CDC can accurately measure differential capacitance even if leakage resistance is present.
dc.language	English
dc.publisher	IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
dc.relation.ispartof	IEEE Sensors Letters
dc.relation.isbasedon	10.1109/LSENS.2024.3355249
dc.rights	info:eu-repo/semantics/closedAccess
dc.subject.classification	4009 Electronics, sensors and digital hardware
dc.title	A Novel Direct Digitizer for Leaky Differential Capacitive Sensors Using Phase Sensitive Integration
dc.type	Journal Article
utslib.citation.volume	8
pubs.organisational-group	University of Technology Sydney
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	University of Technology Sydney/Strength - RI - Robotics Institute
utslib.copyright.status	closed_access	*
dc.date.updated	2024-08-07T04:44:54Z
pubs.issue	2
pubs.publication-status	Published
pubs.volume	8
utslib.citation.issue	2

Abstract:

A novel capacitance to digital converter (CDC), which estimates the capa-citance of a leaky differential capacitive sensor (DCS) based on phase sensitive integration (PSI) is presented in this letter. Various methods to measure the capacitance of a leaky capacitive sensor exist, but all these methods apply to single-element capacitive sensor. Most of the techniques, which measure capacitance of a DCS are sensitive to leakage resistance of the sensor. The proposed CDC works with alternating current excitation and employs PSI along with dual slope operation to estimate differential capacitance independent of the leakage resistance. In addition, the proposed CDC is insensitive to the stray capacitance (due to sensor structure or connecting cables) seen at the sensor terminals. Even though the measurand varies in a linear or nonlinear fashion with respect to sensor characterestics, the ratiometric output of the proposed CDC ensures that the output is linear with respect to the measurand. The prototype of CDC is tested for a wide differential range of ± 220 pF with a nominal value of 400 pF and worst case full scale (F.S) nonlinearity error of < 0.17% is observed. The prototype of CDC is tested for leakage resistance varying from 10 M Ω to 50 k Ω and worst case error of 1.1% is observed. The prototype of CDC is also tested for stray capacitance, varying from 10 to 200 pF and worst case error observed is 0.39%. Thus, the proposed CDC can accurately measure differential capacitance even if leakage resistance is present.

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http://hdl.handle.net/10453/180227