Patent EP0409213A2 successfully refreshed from Google Patents.
EP0409213A2
Expired / Lapsed
EP
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Amplifiying compensation circuit for semiconductor pressure sensor
Assignee: Fuji Electric Co Ltd
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Filing: 1990-07-18
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Granted: —
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Expires: 2010-07-18
Abstract
Abstract A pressure sensor circuit has a bridge circuit of strain gauges (101-104) formed on a silicon diaphragm with two output terminals. The difference in the voltage between the two output terminals is dependent on the pressure applied to the strain gauges. A differential amplifier circuit having an operational amplifier (207) and a feedback circuit amplifies the difference between the two output terminals. A temperature dependent resistor (56) in the feedback circuit provides temperature compensation. An adjustable resistor (21) adjusts the sensitivity of the pressure sensor circuit. Temperature dependent resistors (54,55) connected between the operational amplifier and reference voltages compensate for zero point temperature fluctuations, and adjustable resistors (22,23) connected between the operational amplifier and the reference voltages adjust the zero point.
Inventors
- 👤 Kazuyuki C/O Fuji Electric Co. Ltd. Kato
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 11:13
CPC Classifications
G; G01; G01L; G01L19/00; G01L19/02; G01L1/00; G01L1/20; G01L1/22; G01L1/2268; G01L1/2281; G01L9/00; G01L9/02; G01L9/04; G01L9/045
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
195 words
A pressure sensor circuit, comprising: first and second terminals connected respectively to first and second potentials; means for sensing a pressure and generating first and second voltages interconnected with the first and second terminals, the difference of the first and second voltages being dependent on at least one pressure to be sensed; means for converting impedance comprising a voltage follower circuit which receives the first voltage; means for amplifying the difference between the first and second voltages comprising an operational amplifier with first and second inputs and a feedback circuit with a temperature dependent resistor; means for adjusting the sensitivity of the pressure sensor circuit comprising a resistor with adjustable resistance connected between the pressure sensing means and the first input of the operational amplifier; means for compensating for temperature induced fluctuations in the zero point of the pressure sensor circuit comprising at least one temperature dependent resistor connected between the first input of the operational amplifier and the first terminal; and means for adjusting the zero point of the pressure sensor circuit comprising at least one resistor with an adjustable resistance connected between the first input of the operational amplifier and the first terminal.
Claim 2
Dependent Claim
195 words
A pressure sensor circuit, comprising: first and second terminals connected respectively to first and second potentials; means for sensing a pressure and generating first and second voltages interconnected with the first and second terminals, the difference of the first and second voltages being dependent on at least one pressure to be sensed; means for converting impedance comprising a voltage follower circuit which receives the first voltage; means for amplifying the difference between the first and second voltages comprising an operational amplifier with first and second inputs and a feedback circuit with a temperature dependent resistor; means for adjusting the sensitivity of the pressure sensor circuit comprising a resistor with adjustable resistance connected between the pressure sensing means and the first input of the operational amplifier; means for compensating for temperature induced fluctuations in the zero point of the pressure sensor circuit comprising at least one temperature dependent resistor connected between the first input of the operational amplifier and the first terminal; and means for adjusting the zero point of the pressure sensor circuit comprising at least one resistor with an adjustable resistance connected between the first input of the operational amplifier and the first terminal.
Claim 3
Dependent Claim
21 words
A pressure sensor circuit as claimed in claim 1, wherein the first input of the operational amplifier is the inversion input.
Claim 4
Dependent Claim
26 words
A pressure sensor circuit as claimed in claim 2, wherein the pressure sensor means is a bridge circuit having strain gauges formed on a silicon diaphragm.
Claim 5
Dependent Claim
28 words
A pressure sensor circuit as claimed in claim 3, wherein the feedback circuit further comprises a resistor with adjustable resistance connected in parallel to the temperature dependent resistor.
Claim 6
Dependent Claim
37 words
A pressure sensor circuit as claimed in claim 4, wherein the means for compensating for the temperature induced fluctuations further comprises a resistor with adjustable resistance connected in series with the at least one temperature dependent resistor.
Claim 7
Dependent Claim
237 words
A pressure sensor circuit, comprising: first and second terminals connected respectively to first and second potentials; means for sensing a pressure and generating first and second voltages interconnected with the first and second terminals, the difference of the first and second voltages being dependent on at least one pressure to be sensed; means for converting impedance comprising a voltage follower circuit which receives the first voltage; means for amplifying the difference between the first and second voltages comprising an operational amplifier with first and second inputs and a feedback circuit with a temperature dependent resistor; means for adjusting the sensitivity of the pressure sensor circuit comprising a resistor with adjustable resistance connected between the pressure sensing means and the first input of the operational amplifier; means for compensating for temperature induced fluctuations in the zero point of the pressure sensor circuit comprising at least one temperature dependent resistor connected between the first input of the operational amplifier and the first terminal, and at least one temperature dependent resistor connected between the first input of the operational amplifier and the second terminal; and means for adjusting the zero point of the pressure sensor circuit comprising at least one resistor with an adjustable resistance connected between the first input of the operational amplifier and the first terminal, and at least one resistor with an adjustable resistance connected between the first input of the operational amplifier and the second terminal.
Claim 8
Dependent Claim
237 words
A pressure sensor circuit, comprising: first and second terminals connected respectively to first and second potentials; means for sensing a pressure and generating first and second voltages interconnected with the first and second terminals, the difference of the first and second voltages being dependent on at least one pressure to be sensed; means for converting impedance comprising a voltage follower circuit which receives the first voltage; means for amplifying the difference between the first and second voltages comprising an operational amplifier with first and second inputs and a feedback circuit with a temperature dependent resistor; means for adjusting the sensitivity of the pressure sensor circuit comprising a resistor with adjustable resistance connected between the pressure sensing means and the first input of the operational amplifier; means for compensating for temperature induced fluctuations in the zero point of the pressure sensor circuit comprising at least one temperature dependent resistor connected between the first input of the operational amplifier and the first terminal, and at least one temperature dependent resistor connected between the first input of the operational amplifier and the second terminal; and means for adjusting the zero point of the pressure sensor circuit comprising at least one resistor with an adjustable resistance connected between the first input of the operational amplifier and the first terminal, and at least one resistor with an adjustable resistance connected between the first input of the operational amplifier and the second terminal.
Claim 9
Dependent Claim
21 words
A pressure sensor circuit as claimed in claim 6, wherein the first input of the operational amplifier is the inversion input.
Claim 10
Dependent Claim
26 words
A pressure sensor circuit as claimed in claim 7, wherein the pressure sensor means is a bridge circuit having strain gauges formed on a silicon diaphragm.
Claim 11
Dependent Claim
28 words
A pressure sensor circuit as claimed in claim 8, wherein the feedback circuit further comprises a resistor with adjustable resistance connected in parallel to the temperature dependent resistor.
Claim 12
Dependent Claim
80 words
A pressure sensor circuit as claimed in claim 9, wherein the means for compensating for the temperature induced fluctuations further comprises a resistor with adjustable resistance connected in series with the at least one temperature dependent resistor connected between the first input of the operational amplifier and the first terminal, and a resistor with adjustable resistance connected in series with the at least one temperature dependent resistor connected between the first input of the operational amplifier and the second terminal.
References Cited (Backward Citations)
No citation records indexed.
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