US5488368A
Expired / Lapsed
US
⏱️ 0.0 years remaining
A/D converter system and method with temperature compensation
Assignee: TechnoView Inc
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Filing: 1994-01-13
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Granted: 1996-01-30
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Expires: 2014-01-13
Abstract
Abstract An A/D circuit to convert an analog signal to a digital signal. The circuit includes a low noise analog-to-digital conversion chip and a precision voltage reference source. The voltage reference source includes a diode with two terminals and a passive attenuation circuit. The attenuation circuit and the diode are coupled in parallel between the two terminals to provide a voltage reference signal for use by the analog to digital conversion chip. The analog to digital chip uses the voltage reference signal to set the full scale input range for the signal conversion, and the voltage reference signal is attenuated to correspond to the full scale range of the analog signal. The A/D converter circuit has a passive temperature compensation feature to substantially eliminate or reduce the effects of thermal drift and of operating at different temperatures. Also, the A/D converter circuit can be coupled to a plurality of transducer inputs, such that the A/D converter circuit can measure voltage, current and resistance input signals.
Inventors
- 👤 Eric W. Brown
- 👤 James A. Littlefield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:59
CPC Classifications
G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/18; H; H03; H03M; H03M1/00; H03M1/06; H03M1/08; H03M1/089; H03M1/12
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
153 words
An A/D convertor circuit having low noise for converting an analog signal having a full scale input range into a digital signal, the circuit comprising: an analog-to-digital conversion circuit that produces an uncompensated digital signal; temperature compensation means for adjusting the uncompensated digital signal from the analog-to-digital conversion circuit to produce the digital signal; and wherein the uncompensated digital signal is adjusted to compensate for variances due to the operating temperature of the A/D circuit; and a voltage reference source having a diode with two terminals and a passive attenuation circuit coupled in parallel between the two terminals to provide a voltage reference signal, wherein the analog-to-digital circuit further includes a voltage reference input, wherein the voltage reference source is coupled to the voltage reference input of the analog-to-digital circuit, wherein the voltage reference signal is attenuated by the passive attenuation circuit to approximate the full scale input range of the analog signal.
Claim 2
Dependent Claim
153 words
An A/D convertor circuit having low noise for converting an analog signal having a full scale input range into a digital signal, the circuit comprising: an analog-to-digital conversion circuit that produces an uncompensated digital signal; temperature compensation means for adjusting the uncompensated digital signal from the analog-to-digital conversion circuit to produce the digital signal; and wherein the uncompensated digital signal is adjusted to compensate for variances due to the operating temperature of the A/D circuit; and a voltage reference source having a diode with two terminals and a passive attenuation circuit coupled in parallel between the two terminals to provide a voltage reference signal, wherein the analog-to-digital circuit further includes a voltage reference input, wherein the voltage reference source is coupled to the voltage reference input of the analog-to-digital circuit, wherein the voltage reference signal is attenuated by the passive attenuation circuit to approximate the full scale input range of the analog signal.
Claim 3
Dependent Claim
24 words
A circuit according to claim 1, wherein the A/D convertor circuit further includes an auto-zero circuit to further reduce affects of a system drift.
Claim 4
Dependent Claim
32 words
A circuit according to claim 1, wherein the analog signal is a DC signal, and wherein the A/D convertor circuit further includes circuitry that is adapted to receive and convert DC signals.
Claim 5
Dependent Claim
23 words
A circuit according to claim 1, wherein the A/D convertor circuit further includes a driver circuit to drive at least one analog transducer.
Claim 6
Dependent Claim
31 words
A circuit according to claim 1, wherein the A/D convertor circuit further includes a transducer convertor for converting a resistance into a voltage to be converted by the A/D convertor circuit.
Claim 7
Dependent Claim
30 words
A circuit according to claim 1, wherein the A/D convertor circuit further includes a transducer convertor for converting a current into a voltage for conversion by the A/D convertor circuit.
Claim 8
Dependent Claim
44 words
A circuit according to claim 1, wherein the A/D convertor circuit further includes transducer convertors for converting both a current or a resistance into a voltage for conversion by the A/D convertor circuit, and selection means for selecting current, resistance or voltage sampling functions.
Claim 9
Dependent Claim
154 words
A data acquisition apparatus for converting an analog signal into a digital signal, the apparatus comprising: an analog-to-digital circuit having a voltage reference input; a voltage reference source having a diode with two terminals and a passive attenuation circuit coupled in parallel between the two terminals to provide a voltage reference signal, wherein the voltage reference source is coupled to the voltage reference input of the analog-to-digital circuit, wherein the voltage reference signal is attenuated by the passive attenuation circuit to correspond to the full scale input range of the analog signal; at least one transducer input coupled to the analog to digital circuit for receiving a corresponding at least one transducer signal; and temperature compensation means for adjusting the uncompensated digital signals from the analog-to-digital conversion circuit to produce the digital signal, wherein the uncompensated digital signal is adjusted to compensate for variances due to the operating temperature of the data acquisition apparatus.
Claim 10
Dependent Claim
154 words
A data acquisition apparatus for converting an analog signal into a digital signal, the apparatus comprising: an analog-to-digital circuit having a voltage reference input; a voltage reference source having a diode with two terminals and a passive attenuation circuit coupled in parallel between the two terminals to provide a voltage reference signal, wherein the voltage reference source is coupled to the voltage reference input of the analog-to-digital circuit, wherein the voltage reference signal is attenuated by the passive attenuation circuit to correspond to the full scale input range of the analog signal; at least one transducer input coupled to the analog to digital circuit for receiving a corresponding at least one transducer signal; and temperature compensation means for adjusting the uncompensated digital signals from the analog-to-digital conversion circuit to produce the digital signal, wherein the uncompensated digital signal is adjusted to compensate for variances due to the operating temperature of the data acquisition apparatus.
Claim 11
Dependent Claim
22 words
An apparatus according to claim 8, wherein the apparatus further includes an auto-zero circuit to further reduce affects of a system drift.
Claim 12
Dependent Claim
29 words
An apparatus according to claim 8, wherein the analog signal is a DC signal, wherein the apparatus further includes circuitry that is adapted to receive and convert DC signals.
Claim 13
Dependent Claim
30 words
An apparatus according to claim 8, wherein the at least one transducer input is selected from the group consisting of a voltage input, a current input and a resistance input.
Claim 14
Dependent Claim
32 words
An apparatus according to claim 11, wherein the at least one transducer input includes a transducer convertor for converting a resistance into a voltage to be converted by the analog-to-digital conversion circuit.
Claim 15
Dependent Claim
31 words
An apparatus according to claim 11, wherein the at least one transducer input includes a transducer convertor for converting a current into a voltage for conversion by the analog-to-digital conversion circuit.
Claim 16
Dependent Claim
68 words
An apparatus according to claim 8, wherein the at least one transducer input is a plurality of different transducer inputs, each different transducer input for receiving a corresponding different transducer signal, each different transducer input includes a transducer convertor for converting a voltage, current or a resistance into a voltage for conversion by the A/D convertor circuit, and selection means for selecting current, resistance or voltage sampling functions.
References Cited (Backward Citations)
US4222110A
Cited
JPS5725722A
Cited
JPS5927619A
Cited
JPS59207732A
Cited
US4592002A
Cited
US4654632A
Cited
US5034745A
Cited
US4860011A
Cited
US4733216A
Cited
US4827191A
Cited
US5010347A
Cited
US5023783A
Cited
US4990913A
Cited
US4998106A
Cited
US5027117A
Cited
US4908623A
Cited
US4933676A
Cited
US4999627A
Cited
JPH03254217A
Cited
US5184130A
Cited
US5254992A
Cited
US5319370A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-01-29 | 1999-07-31 | 2000-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-29 | 2003-07-31 | 2004-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-29 | 2007-07-31 | 2008-01-30 | $7700.00 | Window Closed / Lapsed |