READOUT-INTERFACE CIRCUIT FOR A CAPACITIVE MICROELECTROMECHANICAL SENSOR, AND CORRESPONDING SENSOR
First Claim
1. A capacitive sensor comprising:
- a microelectromechanical detection structure having;
a fixed element and a mobile element capacitively coupled to one another and designed to generate a capacitive variation which is a function of a quantity to be detected, anda parasitic coupling element capacitively coupled to at least one of said mobile element and said fixed element, and structured to generate a first parasitic capacitance intrinsic to said detection structure; and
a readout-interface circuit that includes;
an output terminal,an amplification stage electrically coupled to said detection structure and configured to generate, on the output terminal, an output signal according to said capacitive variation, anda feedback path between said output terminal and said parasitic coupling element, configured so as to drive said first parasitic capacitance with said output signal.
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Abstract
In a capacitive sensor, a detection structure, of a microelectromechanical type, is provided with a fixed element and a mobile element, capacitively coupled to one another, generating a capacitive variation as a function of a quantity to be detected, and with a parasitic coupling element, capacitively coupled to at least one between the mobile element and the fixed element generating a first parasitic capacitance, intrinsic to the detection structure; a readout-interface circuit is connected to the detection structure and generates, on an output terminal thereof, an output signal as a function of the capacitive variation. The readout-interface circuit has a feedback path between the output terminal and the parasitic coupling element so as to drive the first intrinsic parasitic capacitance with the output signal.
23 Citations
20 Claims
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1. A capacitive sensor comprising:
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a microelectromechanical detection structure having; a fixed element and a mobile element capacitively coupled to one another and designed to generate a capacitive variation which is a function of a quantity to be detected, and a parasitic coupling element capacitively coupled to at least one of said mobile element and said fixed element, and structured to generate a first parasitic capacitance intrinsic to said detection structure; and a readout-interface circuit that includes; an output terminal, an amplification stage electrically coupled to said detection structure and configured to generate, on the output terminal, an output signal according to said capacitive variation, and a feedback path between said output terminal and said parasitic coupling element, configured so as to drive said first parasitic capacitance with said output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A readout method for a capacitive sensor provided with a microelectromechanical detection structure designed to generate a capacitive variation according to a quantity to be detected, and having at least one first parasitic capacitance intrinsic to said detection structure;
- said method comprising;
generating an output signal as a function of said capacitive variation; and feeding back said first parasitic capacitance with said output signal. - View Dependent Claims (13, 14)
- said method comprising;
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15. A readout-interface circuit for a capacitive sensor that includes a microelectromechanical detection structure having a fixed element and a mobile element capacitively coupled to one another and designed to generate a capacitive variation which is a function of a quantity to be detected, and a parasitic coupling element capacitively coupled to at least one of said mobile element and said fixed element, the readout-interface circuit comprising:
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a first input terminal for coupling to said mobile element; an output terminal; an amplification stage coupled between said first input terminal and said output terminal, the amplification stage being configured to generate, on the output terminal, an output signal according to said capacitive variation; and a conductive path for creating a feedback path between said output terminal and said parasitic coupling element, the conductive path being configured so as to drive said first parasitic capacitance with said output signal, said feedback path being a positive feedback branch of said amplification stage. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification