Patent US4514828A successfully refreshed from Google Patents.
US4514828A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic bubble memory sense amplifier having a pulsed current mode of operation
Assignee: Texas Instruments Inc
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Filing: 1982-01-18
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Granted: 1985-04-30
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Expires: 2002-01-18
Abstract
Abstract A temperature compensated, phase tolerant sense amplifier for use in a magnetic bubble memory system in which current is applied to the detector resistors only during a bubble detect operation.
Inventors
- 👤 Thomas A. Closson
- 👤 David B. Oxford
- 👤 Stephen R. Schenck
- 👤 Jerold A. Seitchik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:56
CPC Classifications
G; G11; G11C; G11C19/00; G11C19/02; G11C19/08; G11C19/0866
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
179 words
A magnetic bubble system comprising: a magnetic bubble device having a plurality of movable magnetic bubbles stored therein, and including a dummy resistor and a detector resistor which alters resistance in response to movement of a magnetic bubble therebeneath; control circuitry connected to said device for periodically removing magnetic bubbles beneath said detector resistor, wherein said control circuitry produces a first control signal when said bubbles are moved; a first current source connected to said dummy resistor for supplying current therethrough; a second current source connected to said detector resistor for supplying current therethrough; a gate coupled to said first and second current sources and to said control circuitry, wherein said gate is responsive to said control signal and causes said first and second current sources to supply current to said dummy and second resistors respectively only when said magnetic bubbles are moving beneath said detector resistor; and comparison circuitry in electrical communication with said dummy resistor and said detector resistor to determine when the resistance of said detector resistor alters in response to the movement of said bubbles.
Claim 2
Dependent Claim
179 words
A magnetic bubble system comprising: a magnetic bubble device having a plurality of movable magnetic bubbles stored therein, and including a dummy resistor and a detector resistor which alters resistance in response to movement of a magnetic bubble therebeneath; control circuitry connected to said device for periodically removing magnetic bubbles beneath said detector resistor, wherein said control circuitry produces a first control signal when said bubbles are moved; a first current source connected to said dummy resistor for supplying current therethrough; a second current source connected to said detector resistor for supplying current therethrough; a gate coupled to said first and second current sources and to said control circuitry, wherein said gate is responsive to said control signal and causes said first and second current sources to supply current to said dummy and second resistors respectively only when said magnetic bubbles are moving beneath said detector resistor; and comparison circuitry in electrical communication with said dummy resistor and said detector resistor to determine when the resistance of said detector resistor alters in response to the movement of said bubbles.
Claim 3
Dependent Claim
169 words
In combination with a magnetic bubble memory system including a magnetic bubble memory device having magnetic bubbles stored therein, a detector resistor which changes resistance in response to the movement of a magnetic bubble therebeneath, a dummy resistor, and control means for moving magnetic bubbles stored in a magnetic memory device beneath the detector resistor, and for providing a control signal while moving the magnetic bubbles, improved sense amplifier comprising: voltage reference means for providing a reference voltage; constant current means for providing a flow of current to each of the resistors at a level determined by an applied voltage, whereby voltages are developed thereacross; gate means for applying the reference voltage to the constant current means in response the control signal, and for applying a disable voltage to the constant current means otherwise, the disable voltage being selected to substantially disable the constant current means; and means for providing an output signal in response to the voltages developed across the resistors differing by at least a threshold voltage.
Claim 4
Dependent Claim
169 words
In combination with a magnetic bubble memory system including a magnetic bubble memory device having magnetic bubbles stored therein, a detector resistor which changes resistance in response to the movement of a magnetic bubble therebeneath, a dummy resistor, and control means for moving magnetic bubbles stored in a magnetic memory device beneath the detector resistor, and for providing a control signal while moving the magnetic bubbles, improved sense amplifier comprising: voltage reference means for providing a reference voltage; constant current means for providing a flow of current to each of the resistors at a level determined by an applied voltage, whereby voltages are developed thereacross; gate means for applying the reference voltage to the constant current means in response the control signal, and for applying a disable voltage to the constant current means otherwise, the disable voltage being selected to substantially disable the constant current means; and means for providing an output signal in response to the voltages developed across the resistors differing by at least a threshold voltage.
Claim 5
Dependent Claim
17 words
The amplifier of claim 2 wherein the current source means includes means for selecting the reference voltage.
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) | 1988-04-29 | 1988-10-29 | 1989-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-29 | 1992-10-29 | 1993-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-29 | 1996-10-29 | 1997-04-30 | $7700.00 | Window Closed / Lapsed |