US3740652A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal selector circuit
Assignee: Monsanto Co
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Filing: 1971-11-17
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Granted: 1973-06-19
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Expires: 1991-11-17
Abstract
Abstract Described herein is an analog signal selector circuit including an input circuit comprising two arrays of semiconductor diodes, all having substantially identical forward-bias characteristics, and an input circuit comprising a noninverting operational amplifier having a feedback loop, in which is operatively connected a forward-biased semi-conductor diode having characteristics matched to those of the two diode arrays. The arrays are connected to input terminals to which discrete analog input signals (DC) are applied. Selective actuation of the diode arrays results in the highest or lowest of the input signals being selected and applied to the operational amplifier, the output of which precisely reproduces the selected input signal, notwithstanding variations in the electrical characteristics of the array diodes as a result of temperature changes.
Inventors
- 👤 W Burgener
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:09
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/0038
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
302 words
A combination high or low signal selector circuit comprising, a plurality of input terminals each adapted to receive separate analog input signals, an output terminal, a first plurality of matched semiconductor diodes having their cathodes coupled together and each of their anodes coupled to a predetermined terminal of said plurality of input terminals, a second plurality of matched semiconductor diodes having their anodes coupled together and each of their cathodes coupled to a predetermined terminal of said plurality of said input terminals, operational amplifier means having first and second input terminals and an output terminal, the output of said amplifier means being coupled to said selector circuit output terminal, said amplifier means including feedback circuit means coupled between its said output terminal and its said second input terminal, first and second semiconductor diodes, said first diode being matched to those diodes of said first plurality of matched diodes and said second diode being matched to those diodes of said second plurality of matched diodes, first and second biasing potential sources for biasing said first and second plurality of matched diodes respectively, and switching means for selectively coupling said cathodes and anodes of said first and second plurality of matched diodes, respectively, to said first input terminal of said amplifier means, selectively coupling said biasing potential sources to said first and second plurality of matched diodes, and selectively including one of said first and second diodes in said feedback circuit of said amplifier means, whereby said switching means may be actuated and the high or low signal applied to said input terminals is selected and accurately reproduced at said output terminal of said selector circuit notwithstanding temperature variations, or the like, said first and second diodes compensating for both threshold voltage drops and impedances of said first and second plurality of matched diodes.
Claim 2
Dependent Claim
302 words
A combination high or low signal selector circuit comprising, a plurality of input terminals each adapted to receive separate analog input signals, an output terminal, a first plurality of matched semiconductor diodes having their cathodes coupled together and each of their anodes coupled to a predetermined terminal of said plurality of input terminals, a second plurality of matched semiconductor diodes having their anodes coupled together and each of their cathodes coupled to a predetermined terminal of said plurality of said input terminals, operational amplifier means having first and second input terminals and an output terminal, the output of said amplifier means being coupled to said selector circuit output terminal, said amplifier means including feedback circuit means coupled between its said output terminal and its said second input terminal, first and second semiconductor diodes, said first diode being matched to those diodes of said first plurality of matched diodes and said second diode being matched to those diodes of said second plurality of matched diodes, first and second biasing potential sources for biasing said first and second plurality of matched diodes respectively, and switching means for selectively coupling said cathodes and anodes of said first and second plurality of matched diodes, respectively, to said first input terminal of said amplifier means, selectively coupling said biasing potential sources to said first and second plurality of matched diodes, and selectively including one of said first and second diodes in said feedback circuit of said amplifier means, whereby said switching means may be actuated and the high or low signal applied to said input terminals is selected and accurately reproduced at said output terminal of said selector circuit notwithstanding temperature variations, or the like, said first and second diodes compensating for both threshold voltage drops and impedances of said first and second plurality of matched diodes.
Claim 3
Dependent Claim
208 words
An analog signal selector circuit, comprising, a plurality of input terminals adapted to receive discrete analog input signals, selector circuit means electrically coupled to said input terminals for establishing a low impedance path for one of said input signals and high impedance paths for all other input signals, said selector circuit means comprising two sets of semiconductor diode arrays, one set being poled to select a high input signal and the other poled to select a low input signal, means providing respective operative-biasing potentials for each of said diode arrays, and switching means for selectively actuating one of said diode arrays and its corresponding biasing potential means, high-gain, DC amplifier means having its input electrically coupled to either of said sets of diode arrays by said switching means, said amplifier means including an output and a feedback circuit between its input and output having an impedance corresponding to that of said low impedance path of said selector circuit means, said feedback circuit impedance selectively comprising at least one of a plurality of forward-biased semiconductor diodes matched to those diodes of said arrays, and whereby the input signal applied to said low impedance path of said selector circuit means is accurately reproduced at said output of said amplifier means.
Claim 4
Dependent Claim
208 words
An analog signal selector circuit, comprising, a plurality of input terminals adapted to receive discrete analog input signals, selector circuit means electrically coupled to said input terminals for establishing a low impedance path for one of said input signals and high impedance paths for all other input signals, said selector circuit means comprising two sets of semiconductor diode arrays, one set being poled to select a high input signal and the other poled to select a low input signal, means providing respective operative-biasing potentials for each of said diode arrays, and switching means for selectively actuating one of said diode arrays and its corresponding biasing potential means, high-gain, DC amplifier means having its input electrically coupled to either of said sets of diode arrays by said switching means, said amplifier means including an output and a feedback circuit between its input and output having an impedance corresponding to that of said low impedance path of said selector circuit means, said feedback circuit impedance selectively comprising at least one of a plurality of forward-biased semiconductor diodes matched to those diodes of said arrays, and whereby the input signal applied to said low impedance path of said selector circuit means is accurately reproduced at said output of said amplifier means.
Claim 5
Dependent Claim
26 words
The analog signal selector circuit as defined in claim 2, wherein all of said semiconductor diodes are matched to have substantially identical electrical and thermal characteristics.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |