Electronic circuit with a capacitive sensor for measuring a physical parameter and method of activating the electronic circuit

摘要

The electronic circuit has a capacitive sensor that includes two capacitors mounted in differential, whose common electrode can move relative to each fixed electrode of the two capacitors to alter the capacitive value of each capacitor. The electronic circuit has an interface connected to the capacitive sensor, which includes a charge transfer amplifier unit connected to the common electrode, an integrator unit, and an excitation unit arranged between the output of the first integrator unit and the sensor to polarise each fixed electrode of the sensor capacitors at a determined voltage value. A compensation capacitor is connected to the input of the integrator unit. The electronic circuit interface includes comparison means for comparing the output voltage with a comparison voltage to control disconnection of the compensation capacitor at the integrator unit input, if the deviation between the output voltage and the comparison voltage exceeds a determined voltage threshold.