US3818246A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switching circuits particularly useful for analog-to-digital converters
Assignee: International Business Machines Corp
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Filing: 1972-12-11
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Granted: 1974-06-18
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Expires: 1992-12-11
Abstract
Abstract Time delays associated with switching controls of analog-todigital converter circuits permit switching transients to be blocked from reducing conversion accuracy. The time delays allow switching to be performed while normal conversion operations are suspended. Appropriate converter components are maintained with quiescent operating levels between conversion cycles so that drifting of those components during conversion cycles is minimized. At least the final portion of a simulated conversion cycle is used as a precedent to each conversion cycle so that the initiating and completing conversion levels are maintained equivalent. A precision semiconductor switch effects on-off switching with constant resistance by referencing the switch control signals to the switch input level.
Inventors
- 👤 G Hellwarth
- 👤 J Milton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:40
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50; H03M1/52
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
84 words
A switching circuit comprising a switching element including at least one semiconductor device having input, output and control terminals, a constant signal source, means responsive to signals introduced to said input terminal for developing a signal proportioned to the difference between the magnitude of said input signal and the magnitude of said constant signal, and isolating means for coupling said proportioned signal to said control terminal for causing said semiconductor device to present a constant resistance between the said input and output terminals thereof.
Claim 2
Dependent Claim
84 words
A switching circuit comprising a switching element including at least one semiconductor device having input, output and control terminals, a constant signal source, means responsive to signals introduced to said input terminal for developing a signal proportioned to the difference between the magnitude of said input signal and the magnitude of said constant signal, and isolating means for coupling said proportioned signal to said control terminal for causing said semiconductor device to present a constant resistance between the said input and output terminals thereof.
Claim 3
Dependent Claim
96 words
Apparatus in accordance with claim 1 wherein said switching element is an FET semiconductor device, said proportioned signal developing means is a differential amplifier having one input thereof coupled in offsetting relation by said constant signal to said input terminal of said switching element, the output of said differential amplifier being coupled to the other input of said differential amplifier means, and said isolating means includes an amplifier coupled to receive said proportioned signal as the main driving source thereof with the output of said amplifier providing signals for said control terminal of said semiconductor device.
Claim 4
Dependent Claim
79 words
Apparatus in accordance with claim 2 which further includes a source of potential for causing said isolating means amplifier to become nonconducting, a command signal generating means, and meaNs responsive to said command signal for selectably energizing said isolating means amplifier with either said proportioned signal or said potential source, whereby said switching element will be off when said amplifier is energized by said potential source but will have a constant input-output resistance when energized by said porportioned signal.
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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) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |