Method and circuit for detecting displacements using micro-electromechanical sensors with compensation of parasitic capacitances and spurious displacements

摘要

A method for detecting displacements of a micro-electromechanical sensor including a fixed body and a mobile mass, and forming a first sensing capacitor and a second sensing capacitor having a common capacitance at rest. The first and second sensing capacitors being connected to a first input terminal and, respectively, to a first output terminal and to a second output terminal of the sensing circuit. The method includes the steps of closing a first negative-feedback loop, which is formed by the first and second sensing capacitors and by a differential amplifier, feeding an input of the differential amplifier with a staircase sensing voltage through driving capacitors so as to produce variations of an electrical driving quantity which are inversely proportional to the common sensing capacitance, and driving the sensor with the electrical driving quantity.