Smart Sensors and MEMS, 2nd Edition

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Capacitive sensors for displacement measurement in the subnanometer range

Sha Xia¹, and Stoyan Nihtianov^2     1NXP Semiconductors, Eindhoven, The Netherlands     ²Delft University of Technology, Delft, The Netherlands

Abstract

The main challenge in designing an interface circuit for capacitive displacement sensors with subnanometer resolution is the large offset capacitance of the sensor. This offset capacitance results from the relatively large distance between the sensor electrodes, compared with the displacement range to be measured. Of the different methods, which interface capacitive sensors, a charge-balancing technique is used here to demonstrate a power-efficient way to remove the offset, while maintaining high resolution and a short conversion ...