A Power-Efficient Readout for Wheatstone-Bridge Sensors With COTS Components

Journal article (2017)

Authors

H. Jiang Electronic Instrumentation - EEMCS
J.G. Vogel Electronic Instrumentation - EEMCS
S. Nihtianova Electronic Instrumentation - EEMCS
Research Group
Electronic Instrumentation (EEMCS) (TU Delft)
Copyright: © 2017 H. Jiang, J.G. Vogel, S. Nihtianova
DOI: https://doi.org/10.1109/JSEN.2017.2755074
Direct digital converter Bridge sensor readout Continuous-time sigma-delta modulator MPa-level differential pressure sensing
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Published Date

2017

Language

English

Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Electronic Instrumentation

Abstract

This paper presents a direct digital converter for Wheatstone bridge sensors, which is realized with commercial off-the-shelf components. The power efficiency of the readout is enhanced by embedding the bridge sensor in a second-order continuous-time sigma-delta modulator (CTDeltaSigmaM). By directly digitizing the output signal of a Wheatstone bridge in the current mode, the noise performance is dominated by the operational amplifier in the first integrator and the bridge sensor. To demonstrate the performance of the proposed circuit, an MEMS piezoresistive differential pressure sensor is used. Measurement results show that a resolution of 12.7 mParms (0.41 mOhmrms), with a 0.5-ms conversion time, can be achieved. Powered by 5 V, the circuit and the bridge sensor draw 9.55 and 7.58 mW, respectively.