发明名称 |
DIFFERENTIAL AMPLIFIER CIRCUIT FOR A CAPACITIVE ACOUSTIC TRANSDUCER AND CORRESPONDING CAPACITIVE ACOUSTIC TRANSDUCER |
摘要 |
An amplifier circuit, for a capacitive acoustic transducer defining a sensing capacitor that generates a sensing signal as a function of an acoustic signal, has a first input terminal and a second input terminal, which are coupled to the sensing capacitor and: a dummy capacitor, which has a capacitance corresponding to a capacitance at rest of the sensing capacitor and a first terminal connected to the first input terminal; a first buffer amplifier, which is coupled at input to the second input terminal and defines a first differential output of the circuit; a second buffer amplifier, which is coupled at input to a second terminal of the dummy capacitor and defines a second differential output of the circuit; and a feedback stage, which is coupled between the differential outputs and the first input terminal, for feeding back onto the first input terminal a feedback signal, which has an amplitude that is a function of the sensing signal and is in phase opposition with respect thereto. |
申请公布号 |
US2016352294(A1) |
申请公布日期 |
2016.12.01 |
申请号 |
US201514960155 |
申请日期 |
2015.12.04 |
申请人 |
STMicroelectronics S.R.L. |
发明人 |
Nicollini Germano;Barbieri Andrea |
分类号 |
H03F3/45;H04R19/00;H04R19/04 |
主分类号 |
H03F3/45 |
代理机构 |
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代理人 |
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主权项 |
1. An amplifier circuit, comprising:
a first input terminal and a second input terminal designed to be electrically coupled to a first terminal and a second terminal of a sensing capacitor configured to generate a sensing signal as a function of an acoustic signal and being part of a sensing structure of a capacitive acoustic transducer; a dummy capacitor having a capacitance corresponding to a respective capacitance at rest in the absence of said acoustic signal, of the sensing capacitor and a respective first terminal connected to the first input terminal; a first buffer amplifier having its non-inverting input terminal coupled to the second input terminal and its inverting input terminal connected to a respective output terminal, which defines a first differential output of said amplifier circuit; a second buffer amplifier having its non-inverting input terminal coupled to a second terminal of the dummy capacitor and its inverting input terminal connected to a respective output terminal, which defines a second differential output of said amplifier circuit, an output signal as a function of said sensing signal being present in use between said first and second differential outputs; and a feedback stage coupled between said first and second differential outputs and said first input terminal and configured to feed back onto said first input terminal a feedback signal, which has an amplitude that is a function of said sensing signal and is in phase opposition with respect to said sensing signal. |
地址 |
Agrate Brianza IT |