A Fully-Differential Switched-Capacitor Dual-Slope Capacitance-To-Digital Converter (CDC) for a Capacitive Pressure Sensor

Rogi, Christopher; Buffa, Cesare; De Milleri, Niccolo; Gaggl, Richard; Prefasi, Enrique

doi:10.3390/s19173673

Open AccessArticle

A Fully-Differential Switched-Capacitor Dual-Slope Capacitance-To-Digital Converter (CDC) for a Capacitive Pressure Sensor

by

Christopher Rogi

^1,*

,

Cesare Buffa

¹,

Niccolo De Milleri

¹,

Richard Gaggl

¹ and

Enrique Prefasi

²

¹

Infineon Technologies Austria AG, RF & Sensors, Siemensstr. 2, 9500 Villach, Austria

²

Electronic Technology Department, Carlos III University of Madrid, 28911 Madrid, Spain

^*

Author to whom correspondence should be addressed.

Sensors 2019, 19(17), 3673; https://doi.org/10.3390/s19173673

Submission received: 9 July 2019 / Revised: 20 August 2019 / Accepted: 21 August 2019 / Published: 23 August 2019

(This article belongs to the Special Issue Advanced Interface Circuits and Systems for Smart Sensors)

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Abstract

This article focuses on a proposed Switched-Capacitor Dual-Slope based CDC. Special attention is paid to the measurement setup using a real pressure sensor. Performance scaling potential as well as dead zones are pointed out and discussed. In depth knowledge of the physical sensor behavior is key to design an optimal readout circuit. While this is true for high-end applications, low-performance IoT (Internet of Things) sensors aim at moderate resolution with very low power consumption. This article also provides insights into basic MEMS (Micro-Electro-Mechanical-System) physics. Based on that, an ambient air pressure sensor model for SPICE (Simulation-Program-with-Integrated-Circuit-Emphasis) circuit simulators is presented. The converter concept was proven on silicon in a 0.13

μ

m process using both a real pressure sensor and an on-chip dummy MEMS bridge. A 3.2-ms measurement results in 13-bit resolution while consuming 35

μ

A from a 1.5-V supply occupying 0.148 mm². A state-of-the-art comparison identifies potential room for improvements towards hybrid solutions, which is proposed in subsequent publications already.

Keywords: MEMS; SPICE model; electro-mechanical coupled simulation; pressure sensor; CDC; Capacitance-to-Digital Converter; Dual-Slope; noise-shaping; auto-zero; switched-capacitor

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MDPI and ACS Style

Rogi, C.; Buffa, C.; De Milleri, N.; Gaggl, R.; Prefasi, E. A Fully-Differential Switched-Capacitor Dual-Slope Capacitance-To-Digital Converter (CDC) for a Capacitive Pressure Sensor. Sensors 2019, 19, 3673. https://doi.org/10.3390/s19173673

AMA Style

Rogi C, Buffa C, De Milleri N, Gaggl R, Prefasi E. A Fully-Differential Switched-Capacitor Dual-Slope Capacitance-To-Digital Converter (CDC) for a Capacitive Pressure Sensor. Sensors. 2019; 19(17):3673. https://doi.org/10.3390/s19173673

Chicago/Turabian Style

Rogi, Christopher, Cesare Buffa, Niccolo De Milleri, Richard Gaggl, and Enrique Prefasi. 2019. "A Fully-Differential Switched-Capacitor Dual-Slope Capacitance-To-Digital Converter (CDC) for a Capacitive Pressure Sensor" Sensors 19, no. 17: 3673. https://doi.org/10.3390/s19173673

APA Style

Rogi, C., Buffa, C., De Milleri, N., Gaggl, R., & Prefasi, E. (2019). A Fully-Differential Switched-Capacitor Dual-Slope Capacitance-To-Digital Converter (CDC) for a Capacitive Pressure Sensor. Sensors, 19(17), 3673. https://doi.org/10.3390/s19173673

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

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A Fully-Differential Switched-Capacitor Dual-Slope Capacitance-To-Digital Converter (CDC) for a Capacitive Pressure Sensor

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