Patent US3624424A successfully refreshed from Google Patents.
US3624424A
Expired / Lapsed
US
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Variable-hysteresis binary trigger circuit
Assignee: AT&T Inc
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Filing: 1970-12-21
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Granted: 1971-11-30
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Expires: 1990-12-21
Abstract
Abstract A resistance bridge is connected between the analog input terminals and a conventional two-input binary trigger to provide variable hysteresis of the input trigger levels. The analog input is connected across one pair of opposite bridge nodes; a transistor is connected across the other pair of opposite bridge nodes. Intermediate taps on a pair of opposite bridge arms are connected to the respective trigger inputs. Changes in the transistor current, which may be controlled by base drive current, produce corresponding changes in the hysteresis of the trigger levels. Equal resistance and equal tap setting of opposite bridge arms produces symmetrical hysteresis control.
Inventors
- 👤 Sun Chun Ping
- 👤 Frank Fuller Judd
- 👤 Jan Mark Lieberman
- 👤 Helmut Wilhart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:47
CPC Classifications
H; H03; H03K; H03K3/00; H03K3/02; H03K3/027; H03K3/037; H03K3/0377; H03K3/26; H03K3/28; H03K3/281; H03K3/286; H03K3/2893
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
149 words
A variable-hysteresis binary trigger circuit comprising a binary trigger having first and second trigger inputs and a binary output; first and second analog-voltage input terminals; and a variable-resistance bridge comprising a first resistance arm and a tapped second resistance arm connected to said first analog-voltage input terminal, a tapped third resistance arm connected between said first resistance arm and said second analog-voltage input terminal, a fourth resistance arm connected between said second resistance arm and said second analog-voltage input terminal and variable conductance means connecting the junction between said first and third resistance arms and the junction between said second and fourth resistance arms, the tap on said second resistance arm being connected to said first trigger input and the tap on said third resistance arm being connected to said second trigger input, whereby the hysteresis of said circuit is controlled by the conductivity of said variable conductance means.
Claim 2
Dependent Claim
149 words
A variable-hysteresis binary trigger circuit comprising a binary trigger having first and second trigger inputs and a binary output; first and second analog-voltage input terminals; and a variable-resistance bridge comprising a first resistance arm and a tapped second resistance arm connected to said first analog-voltage input terminal, a tapped third resistance arm connected between said first resistance arm and said second analog-voltage input terminal, a fourth resistance arm connected between said second resistance arm and said second analog-voltage input terminal and variable conductance means connecting the junction between said first and third resistance arms and the junction between said second and fourth resistance arms, the tap on said second resistance arm being connected to said first trigger input and the tap on said third resistance arm being connected to said second trigger input, whereby the hysteresis of said circuit is controlled by the conductivity of said variable conductance means.
Claim 3
Dependent Claim
30 words
A variable-hysteresis trigger circuit as in claim 1 wherein said variable conductance means includes a control input terminal for varying the conductance in response to a control signal applied thereto.
Claim 4
Dependent Claim
23 words
A variable-hysteresis trigger circuit as in claim 2 wherein the values of resistance of said first and fourth resistance arms are substantially equal.
Claim 5
Dependent Claim
35 words
A variable-hysteresis trigger circuit as in claim 2 wherein said variable conductance means comprises a transistor having its collector-emitter path connected between said bridge arm junctions and its base connected to said control input terminal.
Claim 6
Dependent Claim
38 words
A variable-hysteresis trigger circuit as in claim 3 wherein the resistance values of said second and third resistance arms are larger than the resistance values of said first and fourth resistance arms and substantially equal to each other.
Claim 7
Dependent Claim
19 words
A variable-hysteresis trigger circuit as in claim 4 wherein said binary trigger comprises a plurality of interconnected logic gates.
Claim 8
Dependent Claim
93 words
A variable-hysteresis trigger circuit as in claim 6 wherein said binary trigger comprises a signal inverter and first and second NOR gates, the output of said first NOR gate being connected to a first input of said second NOR gate, the output of said second NOR gate being connected to a first input of said first NOR gate, a second input of said first NOR gate being connected to said second trigger input and a second input of said second NOR gate being connected through said signal inverter to said first trigger input.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-29 | 1975-05-31 | 1975-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-29 | 1979-05-31 | 1979-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-29 | 1983-05-31 | 1983-11-30 | $7700.00 | Window Closed / Lapsed |