Switched-capacitor transducers with digital or duty-cycle output based on pulse-width modulation technique

1 August 1991

journal article
research article
Published by Taylor & Francis in International Journal of Electronics

Vol. 71 (2) , 265-278
https://doi.org/10.1080/00207219108925474

Abstract

New switched-capacitor transducers for capacitive or resistive sensors have been developed based on a pulse-width modulation technique. The output signal is a duty-cycle modulated square-wave voltage or a binary-coded digital signal which can be accurately related to the value of the unknown capacitance or resistance. Several different configurations of transducers have been proposed to meet different requirements and/or to compensate parasitic and non-ideal effects such as the offset voltage and noise of an op.-amp., stray capacitances and the parasitic charge injection due to the clock feedthrough effect of MOS switches. The properties of the proposed transducers and their performance are demonstrated using computer simulation.

Keywords

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