Energy-Efficient Capacitance-to-Digital Converters for Smart Sensor Applications

Handle URI:
http://hdl.handle.net/10754/626955
Title:
Energy-Efficient Capacitance-to-Digital Converters for Smart Sensor Applications
Authors:
Alhoshany, Abdulaziz ( 0000-0002-1976-2545 )
Abstract:
One of the key requirements in the design of wireless sensor nodes and miniature biomedical devices is energy efficiency. For a sensor node, which is a sensor and readout circuit, to survive on limited energy sources such as a battery or harvested energy, its energy consumption should be minimized. Capacitive sensors are candidates for use in energy-constrained applications, as they do not consume static power and can be used in a wide range of applications to measure different physical, chemical or biological quantities. However, the energy consumption is dominated by the capacitive interface circuit, i.e. the capacitance-to-digital converter (CDC). Several energy-efficient CDC architectures are introduced in this dissertation to meet the demand for high resolution and energy efficiency in smart capacitive sensors. First, we propose an energy-efficient CDC based on a differential successive-approximation data converter. The proposed differential CDC employs an energy-efficient operational transconductance amplifier (OTA) based on an inverter. A wide capacitance range with fine absolute resolution is implemented in the proposed coarse-fine DAC architecture which saves 89% of silicon area. The proposed CDC achieves an energy efficiency figure-of-merit (𝐹𝑂𝑀) of 45.8fJ/step, which is the best reported energy efficiency to date. Second, we propose an energy efficient CDC for high-precision capacitive resolution by using oversampling and noise shaping. The proposed CDC achieves 150 aF absolute resolution and an energy efficiency 𝐹𝑂𝑀 of 187fJ/conversion-step which outperforms state of the art high-precision differential CDCs. In the third and last part, we propose an in-vitro cancer diagnostic biosensor-CMOS platform for low-power, rapid detection, and low cost. The introduced platform is the first to demonstrate the ability to screen and quantify the spermidine/spermine N1 acetyltransferase (SSAT) enzyme which reveals the presence of early-stage cancer, on the surface of a capacitive biosensor. This platform, which is a biosensor combined with a highly energy-efficient digital CDC, is implemented and fabricated in a CMOS technology and can sense and convert the capacitance value from the biosensor to a digital word in an energy efficient way. The platform achieves an ultra-low power consumption: four orders of magnitude less than the state-of-the-art biosensor-CMOS platforms.
Advisors:
Salama, Khaled N. ( 0000-0001-7742-1282 )
Committee Member:
Ooi, Boon S. ( 0000-0001-9606-5578 ) ; Younis, Mohammad I. ( 0000-0002-9491-1838 ) ; Abshire, Pamela
KAUST Department:
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Program:
Electrical Engineering
Issue Date:
Dec-2017
Type:
Dissertation
Appears in Collections:
Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.advisorSalama, Khaled N.en
dc.contributor.authorAlhoshany, Abdulazizen
dc.date.accessioned2018-01-30T10:58:11Z-
dc.date.available2018-01-30T10:58:11Z-
dc.date.issued2017-12-
dc.identifier.urihttp://hdl.handle.net/10754/626955-
dc.description.abstractOne of the key requirements in the design of wireless sensor nodes and miniature biomedical devices is energy efficiency. For a sensor node, which is a sensor and readout circuit, to survive on limited energy sources such as a battery or harvested energy, its energy consumption should be minimized. Capacitive sensors are candidates for use in energy-constrained applications, as they do not consume static power and can be used in a wide range of applications to measure different physical, chemical or biological quantities. However, the energy consumption is dominated by the capacitive interface circuit, i.e. the capacitance-to-digital converter (CDC). Several energy-efficient CDC architectures are introduced in this dissertation to meet the demand for high resolution and energy efficiency in smart capacitive sensors. First, we propose an energy-efficient CDC based on a differential successive-approximation data converter. The proposed differential CDC employs an energy-efficient operational transconductance amplifier (OTA) based on an inverter. A wide capacitance range with fine absolute resolution is implemented in the proposed coarse-fine DAC architecture which saves 89% of silicon area. The proposed CDC achieves an energy efficiency figure-of-merit (𝐹𝑂𝑀) of 45.8fJ/step, which is the best reported energy efficiency to date. Second, we propose an energy efficient CDC for high-precision capacitive resolution by using oversampling and noise shaping. The proposed CDC achieves 150 aF absolute resolution and an energy efficiency 𝐹𝑂𝑀 of 187fJ/conversion-step which outperforms state of the art high-precision differential CDCs. In the third and last part, we propose an in-vitro cancer diagnostic biosensor-CMOS platform for low-power, rapid detection, and low cost. The introduced platform is the first to demonstrate the ability to screen and quantify the spermidine/spermine N1 acetyltransferase (SSAT) enzyme which reveals the presence of early-stage cancer, on the surface of a capacitive biosensor. This platform, which is a biosensor combined with a highly energy-efficient digital CDC, is implemented and fabricated in a CMOS technology and can sense and convert the capacitance value from the biosensor to a digital word in an energy efficient way. The platform achieves an ultra-low power consumption: four orders of magnitude less than the state-of-the-art biosensor-CMOS platforms.en
dc.language.isoenen
dc.subjectcapacitative sensor interfaceen
dc.subjectCDCen
dc.subjectenergy-efficienten
dc.subjectcapacitive biosensoren
dc.subjectfigure of merit (FOM)en
dc.subjectCMOSen
dc.titleEnergy-Efficient Capacitance-to-Digital Converters for Smart Sensor Applicationsen
dc.typeDissertationen
dc.contributor.departmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen
dc.contributor.committeememberOoi, Boon S.en
dc.contributor.committeememberYounis, Mohammad I.en
dc.contributor.committeememberAbshire, Pamelaen
thesis.degree.disciplineElectrical Engineeringen
thesis.degree.nameDoctor of Philosophyen
dc.person.id129277en
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