Patent ID: 8629685

Claim:
A device for measuring a variation (ΔC X ) in the capacitance of a variable capacitive structure (C X ), comprising: a supply voltage (V CC ); means for charging the variable capacitive structure (C X ) using the supply voltage (V CC ); means for discharging the variable capacitive structure (C X ) into a reference capacitance (C S ) in a fixed number (x) of discharges; means for measuring a voltage (V S ) across the terminals of the reference capacitance; means for charging a measurement capacitive structure (C M ) using the supply voltage (V CC ); means for discharging the measurement capacitive structure (C M ) into the reference capacitance (C S ) in a variable number (n) of discharges; and means for detecting a threshold voltage (V TH ) across the terminals of the reference capacitance (C S ), characterized in that the device is configured/programmed so that the discharge of the measurement capacitive structure (C M ), in a variable number (n) of discharges, into the reference capacitance (C S ) is carried out after the variable capacitive structure (C X ) has been discharged, in the fixed number (x) of discharges, into the reference capacitance (C S ), and in that the variation in the variable number (n) of discharges relative to a previously obtained number of discharges allows the variation (ΔC X ) in the capacitance of the variable capacitive structure (C X ) to be estimated.