Author ORCID Identifier

https://orcid.org/0000-0002-0738-8218 Hamidreza Esmaeili Taheri

Date of Award

5-7-2021

Publication Type

Dissertation

Degree Name

Ph.D.

Department

Electrical and Computer Engineering

Keywords

Lab-on-Chips, Capacitive biosensors, Voltage and digital output, Pulse width

Supervisor

M. Mirhassani

Supervisor

C. Chang

Rights

info:eu-repo/semantics/embargoedAccess

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

CMOS-based capacitive Lab-on-Chips (LoCs) have shown superior performance in terms of size, power consumption, noise performance, common mode based error immunity, and simplicity. Conventionally, a CMOS readout circuit can produce three different output signals (voltage, digital, and frequency), in response to capacitance variations. This project describes four different readout circuits for capacitive biosensors, two with a voltage output, one with a digital output, and a novel readout circuit that translates capacitance variations to pulse width. The two readout circuits with a voltage output achieve the highest reported resolutions in the literature, i.e. 1 aF, and 5 aF. In both cases, the power consumption of the readout is improved one order of magnitude. The novel capacitance to pulse width conversion technique, delivers a 10 aF resolution with a power consumption of 7.92 uW. The fundamentals of the readout circuit in capacitive biosensors have been reviewed, and the main requirements along with the main available readout techniques are discussed. The four proposed readout approaches are explained, and their performance characteristics are discussed. Compared with the available readout mechanisms, the proposed readout circuits show superior performance in terms of resolution, power consumption, dynamic range, and adaptive sensitivity.

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