Power-Efficiency Evolution of Capacitive Sensor Interfaces

Power-Efficiency Evolution of Capacitive Sensor Interfaces

Tan, Zhichao (Zhejiang University)
Jiang, H. (TU Delft Electronic Instrumentation)
Zhang, H. (TU Delft Electronic Instrumentation)
Tang, Xiyuan (The University of Texas at Austin)
Xin, Haoming (Eindhoven University of Technology)
Nihtianova, S. (TU Delft Electronic Instrumentation)

2021

Recent years have witnessed an improvement in the energy efficiency of capacitive sensor interfaces by more than three orders of magnitude. This article reviews the architectural and circuit innovations that have contributed to this progress. The fundamental limit on the energy consumption of capacitive sensor interfaces is discussed, as well as the widely used figure-of-merit (FoM). Interfaces based on period modulation feature simple circuitry, but their power efficiency at higher resolution deteriorates. Those employing Δ Σ modulation achieve high resolution with improved efficiency but require operational transconductance amplifiers that do not easily scale with process and supply voltage. Interfaces using successive approximation techniques feature mostly digital circuitry achieving good power efficiency at medium resolution. To achieve higher resolution, they can also be employed as the front-end in a hybrid architecture, where a back-end based on Δ Σ modulation or a voltage-controlled oscillator (VCO) performs a fine measurement on the front-end's residue, resulting in high resolution and excellent energy efficiency simultaneously.

Capacitive sensor
energy efficiency
period modulation
SAR
VCO
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http://resolver.tudelft.nl/uuid:113adb79-df7c-4217-a2af-c304203b33c2

https://doi.org/10.1109/JSEN.2020.3035109

1530-437X

IEEE Sensors Journal, 21 (11), 12457-12468

Accepted author manuscript

Institutional Repository

journal article

© 2021 Zhichao Tan, H. Jiang, H. Zhang, Xiyuan Tang, Haoming Xin, S. Nihtianova