Patent US3671772A successfully refreshed from Google Patents.
US3671772A
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US
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Difference amplifier
Assignee: International Business Machines Corp
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Filing: 1969-10-01
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Granted: 1972-06-20
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Expires: 1989-10-01
Abstract
Abstract A difference amplifier used as a sense amplifier for stored binary data being read from a computer memory. The amplifier includes a pair of cross-coupled transistors, a power source providing an operating voltage for said transistors, and means for intermittently applying said power source to the crosscoupled transistors. Selective application means apply each of the pair of voltage signals to be differentiated from each other to a respective one of the pair of cross-couplings, i.e., the pair of cross-connected regions in the transistors. In the case of reading from binary storage, the voltage signals are applied from the pair of sense lines from the memory storage. The signals are applied during a period when the voltage source is not being applied and, consequently, both of the paired transistors are in the non-conductive state. The signals establish a stored charge in each of the transistors; the difference between these charges will determine which of the transistors assumes the conductive state when the power is subsequently applied.
Inventors
- 👤 Robert A Henle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:36
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/01; H03K5/02; G; G11; G11C; G11C11/00; G11C11/02; G11C11/06; G11C11/06007; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/403; G11C11/404; G11C11/4063; G11C11/407; G11C11/409; G11C11/4091; G11C7/00; G11C7/06; G11C7/065
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
207 words
A monolithic integrated semiconductor difference amplifier circuit comprising bistable circuit means comprising a pair of cross-coupled transistors, a power source for said bistable circuit means providing an operating voltage for said circuit means, means for intermittently applying said power source to said bistable circuit means, said cross-coupled transistors being non-conductive when said power source is not being applied, means for applying each of a pair of voltage signals to be differentiated from each other to a respective one of the cross-couplings prior to an application of the power source whereby said signals establish a stored charge in each of said transistors, the difference between said charges determining which one of said transistors assumes the conductive state upon the application of the power source, said pair of voltage signals differing from each other by 0.1V or less, and load impedance means for each transistor through which said power source is applied, said impedance means including semiconductor switch means, responsive to an interruption in the application of the power source, to provide a high impedance discharge path for the stored charge in the transistors when the power source is not being applied and said load impedance having a greater resistance than the crosscoupling resistance between transistors at all times.
Claim 2
Dependent Claim
207 words
A monolithic integrated semiconductor difference amplifier circuit comprising bistable circuit means comprising a pair of cross-coupled transistors, a power source for said bistable circuit means providing an operating voltage for said circuit means, means for intermittently applying said power source to said bistable circuit means, said cross-coupled transistors being non-conductive when said power source is not being applied, means for applying each of a pair of voltage signals to be differentiated from each other to a respective one of the cross-couplings prior to an application of the power source whereby said signals establish a stored charge in each of said transistors, the difference between said charges determining which one of said transistors assumes the conductive state upon the application of the power source, said pair of voltage signals differing from each other by 0.1V or less, and load impedance means for each transistor through which said power source is applied, said impedance means including semiconductor switch means, responsive to an interruption in the application of the power source, to provide a high impedance discharge path for the stored charge in the transistors when the power source is not being applied and said load impedance having a greater resistance than the crosscoupling resistance between transistors at all times.
Claim 3
Dependent Claim
14 words
The difference amplifier of claim 1 wherein said cross-coupled transistors have a common emitter.
Claim 4
Dependent Claim
14 words
The difference amplifier of claim 1 wherein said semiconductor switch comprises unilateral conduction means.
Claim 5
Dependent Claim
13 words
The difference amplifier of claim 1 wherein said semiconductor switch comprises a diode.
Claim 6
Dependent Claim
19 words
The difference amplifier of claim 1 wherein said pair of transistors are bipolar transistors having cross-coupled collectors and bases.
Claim 7
Dependent Claim
20 words
The difference amplifier of claim 1 wherein said pair of transistors are field effect transistors having cross-coupled drains and gates.
Claim 8
Dependent Claim
28 words
The difference amplifier of claim 1 wherein said power source is applied before the stored charges become ineffective for determining which of the transistors assumes the conductive state.
Claim 9
Dependent Claim
19 words
The difference amplifier of claim 1 wherein both transistors are non-conductive when the power source is not being applied.
References Cited (Backward Citations)
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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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |