Micromechanical device for enhanced acceleration measurement

A measurement device, comprising:

• a micromechanical device that includes:
• a semiconductor body having a surface;
• a movable structure facing the surface of the semiconductor body and having an opening in a central region;
• a first measurement electrode extending from the movable structure in the opening, the first measurement electrode extending towards a first side of the movable structure;
• and
• two second measurement electrodes fixed to the semiconductor body and in the opening of the movable structure, the first measurement electrode between the two second measurement electrodes;
• a control structure that includes:
• a first control electrode extending from the first side of the movable structure and away from the opening in the movable structure;
• and
• two second control electrodes fixed to the semiconductor body, the first control electrode extending between the two second control electrodes;
• an elastic assembly which has an equivalent elastic constant (Keq), is mechanically coupled to the movable structure and is configured to elongate and contract along an oscillation direction to allow the oscillation of the movable structure as a function of a force applied to the movable structure along said oscillation direction, said force being caused by an acceleration applied to the micromechanical device the micromechanical device having a total elastic constant (Kt) which is a function of the equivalent elastic constant (Keq) and which is variable over time as a function of capacitive control by the control structure;
• and
• a control unit electrically coupled to the micromechanical device and configured to:
• control, in a first time interval (T1), the control structure in a first state to have the micromechanical device in a first operating mode wherein the total elastic constant (Kt) has a first value;
• acquire, in the first time interval (T1) and through the micromechanical device, a first value (Sm1) of a measurement signal (Sm), the first value (Sm1) of the measurement signal (Sm) being indicative of a first acceleration value (A1) measured by the micromechanical device in the first operating mode;
• determine the first acceleration value (A1) on the basis of the first value (Sm1) of the measurement signal (Sm);
• control, as a function of the first acceleration value (A1) and in a second time interval (T2) consecutive to the first time interval (T1), the control structure in a second state to have the micromechanical device in a second operating mode wherein the total elastic constant (Kt) has a second value lower than, or equal to, the first value;
• acquire, in the second time interval (T2) and through the micromechanical device, a second value (Sm2) of the measurement signal (Sm), the second value (Sm2) of the measurement signal (Sm) being indicative of a second acceleration value (A2) measured by the micromechanical device in the second operating mode;
• and
• determine the second acceleration value (A2) on the basis of the second value (Sm2) of the measurement signal (Sm).

A control method of a measurement device, comprising:

• controlling, by a control unit coupled to a micromechanical device, in a first time interval, a control structure of a movable structure and semiconductor body in a first state to have the micromechanical device in a first operating mode wherein a total elastic constant has a first value;
• acquiring, by the control unit, in the first time interval and through the micromechanical device, a first value of a measurement signal, the first value of the measurement signal being indicative of a first acceleration value measured by the micromechanical device in the first operating mode;
• determining, by the control unit, the first acceleration value based on the first value of the measurement signal;
• controlling, by the control unit, as a function of the first acceleration value and in a second time interval consecutive to the first time interval, the control structure in a second state to have the micromechanical device in a second operating mode wherein the total elastic constant has a second value lower than, or equal to, the first value of the total elastic constant;
• acquiring, by the control unit, in the second time interval and through the micromechanical device, a second value of the measurement signal, the second value of the measurement signal being indicative of a second acceleration value measured by the micromechanical device in the second operating mode;
• and
• determining, by the control unit, the second acceleration value based on the second value of the measurement signal.

A device, comprising:

• a substrate;
• a mass over the substrate, the mass including:
• a first electrode extending from a first side of the mass;
• a central opening;
• and
• a second electrode coupled to the mass and in the central opening, the second electrode extending towards the first electrode of the mass;
• a plurality of measurement electrodes coupled to the substrate, the first electrode extending between the plurality of first measurement electrodes;
• a plurality of control electrodes coupled to the substrate, the second electrode extending between the plurality of control electrodes;
• and
• a first spring assembly having a first end coupled to the substrate, the first spring assembly having a second end, opposite the first end, coupled to a second side of the mass, the second side of the mass transverse to the first side of the mass.