Compensation circuit, corresponding device and method

A method, comprising:

• coupling a first input node and a second input node to a first sensing capacitor and a second sensing capacitor, respectively, of an accelerometer sensor, wherein the first and second sensing capacitors are charged to a first charge and a second charge and exhibit a capacitance unbalance in response to acceleration applied to the accelerometer sensor;
• coupling to the first and second input nodes a first differential stage configured to provide between output nodes thereof a differential signal indicative of a difference between the second charge and the first charge wherein said difference is indicative of acceleration applied to the accelerometer sensor;
• coupling to the first input node and to the second input node a first input and a second input of a second differential stage, respectively, and coupling to a third input of the second differential stage a reference voltage, wherein the second differential stage provides at an output thereof a common mode signal based on a difference between the reference voltage and a voltage indicative of a mean value of a voltage at the first input and a voltage at the second input, wherein said common mode signal is indicative of the sum between the second charge and the first charge;
• and
• converting a ratio of said differential signal to said common mode signal to output a digital signal;
• and
• providing in the second differential stage:
• a first capacitive feedback path having a first capacitance value from the output of the second differential stage to the first input node, and
• a second capacitive feedback path having a second capacitance value from the output of the second differential stage to the second input node;
• wherein the first capacitance value is different from the second capacitance value.

A circuit, comprising:

• a first differential stage having first and second input nodes configured to receive signals from an accelerometer sensor and generate at output nodes a differential signal indicative of an acceleration applied to the accelerometer sensor;
• a second differential stage having first and second inputs coupled, respectively, to the first and second input nodes of the first differential stage, and a third input coupled to a reference voltage, wherein the second differential stage is configured to generate a common mode signal based on a difference between the reference voltage and a voltage indicative of a mean value between the signals at the first and second input nodes;
• and
• an analog-to-digital converter configured to generate a digital output signal from a conversion of a ratio of said differential signal to said common mode signal;
• wherein the second differential stage comprises:
• a first capacitive feedback path, having a first capacitance value, connected between an output of the second differential stage and the first input node;
• and
• a second capacitive feedback path, having a second capacitance value, connected between the output of the second differential stage and the second input node;
• wherein the first capacitance value is different from the second capacitance value.