Demodulator for in-phase and quadrature modulated signals, MEMS gyroscope including the same and demodulation method

A control and sensing circuit for a MEMS gyroscope, comprising:

• a demodulator including,
• a register configured to store a phase calibration value having an integer part and a fractional part;
• a noise-shaping modulator configured to generate a succession of quantized values of integer type, the quantized values having a mean equal to the phase calibration value;
• a generation circuit configured to generate a demodulating signal phase locked with an input signal modulated in-phase and quadrature, the demodulating signal having a phase which depends linearly on the quantized values;
• and
• a demodulation circuit configured to demodulate the input signal through the demodulating signal;
• and
• a driving circuit configured to be coupled to an oscillating system that generates the input signal, the driving circuit configured to generate a clock signal and to provide the oscillating system with a driving signal having a first frequency.

A MEMS gyroscope, comprising:

• a control and sense circuit including:
• a demodulator including,
• a register configured to store a phase calibration value having an integer part and a fractional part;
• a noise-shaping modulator configured to generate a succession of quantized values of integer type, the quantized values having a mean equal to the phase calibration value;
• a generation circuit configured to generate a demodulating signal phase locked with an input signal modulated in-phase and quadrature, the demodulating signal having a phase which depends linearly on the quantized values;
• and
• a demodulation circuit configured to demodulate the input signal through the demodulating signal;
• and
• a driving circuit configured to receive the input signal, the driving circuit configured to generate a clock signal and to provide the oscillating system with a driving signal having a first frequency;
• and
• oscillating system coupled to the driving circuit and configured to generate the input signal, the input signal being indicative of an angular velocity experienced by the MEMS gyroscope.

A method for demodulating an in-phase component of an input signal that is in-phase and quadrature modulated, the method comprising:

• storing a phase calibration value having an integer part and a fractional part;
• generating a succession of quantized values of integer type, the quantized values having a mean equal to the phase calibration value;
• generating a demodulating signal phase locked with the input signal, the demodulating signal having a phase which depends linearly on the quantized values;
• and
• demodulating the input signal by means of the demodulating signal.

A method, comprising:

• performing a calibration of a MEMS gyroscope that includes arranging the MEMS gyroscope in a way in which it experiences a known or zero angular velocity;
• for each value of a plurality of test values, each test value having an integer part and a fractional part, the method including:
• storing the test value;
• generating through a noise-shaping modulator a succession of quantized values of the integer type, quantized values having a mean equal to the test value;
• generating a corresponding demodulating signal phase locked with a sense signal generated by the MEMS gyroscope when experiencing the known or zero angular velocity, the demodulating signal having a phase which depends linearly on the quantized values;
• and
• through the corresponding demodulating signal, demodulating a sense signal generated by the MEMS gyroscope to generate a corresponding base band signal;
• selecting the test value that provides the corresponding base band signal having the smallest quadrature error;
• and
• storing the selected test value.