US3820086A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Read only memory(rom)superimposed on read/write memory(ram)
Assignee: International Business Machines Corp
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Filing: 1972-05-01
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Granted: 1974-06-25
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Expires: 1992-05-01
Abstract
Abstract The disclosures describes a transistor storage cell operable both as a random access read/write memory cell or as a read only memory cell. The memory cell structure includes a bistable circuit adapted to be set into one of two stable conditions and an imbalancing means for providing structural asymmetry. The memory cell is operable either as a read/write cell or, by accessing the cell through the imbalancing means, the latent image provided by the structural asymmetry of the cell is read out without affecting the information contained in the cell from the read/write mode of operation.
Inventors
- 👤 I Ho
- 👤 G Maley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:03
CPC Classifications
G; G11; G11C; G11C7/00; G11C7/20; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/41; G11C11/411; G11C11/4116; G11C17/00; G11C17/08; G11C17/10; G11C17/12; H; H03; H03K; H03K3/00; H03K3/02; H03K3/26; H03K3/28; H03K3/281; H03K3/286; H03K3/353; H03K3/356; H03K3/356008; H03K3/356017; H03K3/356052; H03K3/35606
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
105 words
An information storage apparatus operable both as a read/write memory and as a read only memory comprising: at least one information storage cell adapted to be set iNto more than one condition representing writable stored information; means electrically coupled to said information storage cell for setting said information storage cell into one of said at least more than one conditions; imbalancing means electrically coupled to said information storage cell for selectively introducing structural asymmetry into said information storage cell; and means for sensing the readable only stored information without changing the said one of said at least more than one conditions representing writable stored information.
Claim 2
Dependent Claim
105 words
An information storage apparatus operable both as a read/write memory and as a read only memory comprising: at least one information storage cell adapted to be set iNto more than one condition representing writable stored information; means electrically coupled to said information storage cell for setting said information storage cell into one of said at least more than one conditions; imbalancing means electrically coupled to said information storage cell for selectively introducing structural asymmetry into said information storage cell; and means for sensing the readable only stored information without changing the said one of said at least more than one conditions representing writable stored information.
Claim 3
Dependent Claim
98 words
A read/write memory cell operable as a read only memory without disturbing the read/write information contained therein comprising: a bistable circuit adapted to be set into one of two stable conditions representing writable stored information; means electrically coupled to said bistable circuit for setting said bistable circuit into one of its two stable conditions; imbalancing means integral with said bistable circuit for selectively introducing structural asymmetry into said circuit and representing readable only stored information; and means for sensing the readable only stored information without changing the said one of two stable conditions representing the writable stored information.
Claim 4
Dependent Claim
98 words
A read/write memory cell operable as a read only memory without disturbing the read/write information contained therein comprising: a bistable circuit adapted to be set into one of two stable conditions representing writable stored information; means electrically coupled to said bistable circuit for setting said bistable circuit into one of its two stable conditions; imbalancing means integral with said bistable circuit for selectively introducing structural asymmetry into said circuit and representing readable only stored information; and means for sensing the readable only stored information without changing the said one of two stable conditions representing the writable stored information.
Claim 5
Dependent Claim
15 words
Apparatus as in claim 2 wherein the imbalancing means is connected to a word line.
Claim 6
Dependent Claim
30 words
Apparatus as in claim 2 in which said means for sensing the readable only stored information without changing the writable stored information includes means for sensing the writable stored information.
Claim 7
Dependent Claim
12 words
Apparatus as in claim 2 where the imbalancing means is a diode.
Claim 8
Dependent Claim
13 words
Apparatus as in claim 5 where the diode is a Schottky barrier diode.
Claim 9
Dependent Claim
18 words
Apparatus as in claim 2 wherein said read/write memory cell is constructed in accordance with integrated circuit technology.
Claim 10
Dependent Claim
18 words
Apparatus as in claim 7 wherein said imbalancing means is connected to the substrate of said integrated circuit.
Claim 11
Dependent Claim
27 words
Apparatus as in claim 7 in which said bistable circuit adapted to be set into one of two stable conditions is connected to a bilevel power source.
Claim 12
Dependent Claim
99 words
A read/write memory cell operable as a read only memory without disturbing the read/write information contained therein comprising: a bistable circuit adapted to set into one of two stable conditions representing writable stored information; means electrically coupled to said bistable circuit for setting said bistable circuit into one of its two stable conditions; imbalancing means electrically coupled to said bistable circuit for selectively introducing structural asymmetry into said bistable circuit and representing readable only stored information; and means for sensing the readable only stored information without changing tbe said one of two stable conditions representing the writable stored information.
Claim 13
Dependent Claim
99 words
A read/write memory cell operable as a read only memory without disturbing the read/write information contained therein comprising: a bistable circuit adapted to set into one of two stable conditions representing writable stored information; means electrically coupled to said bistable circuit for setting said bistable circuit into one of its two stable conditions; imbalancing means electrically coupled to said bistable circuit for selectively introducing structural asymmetry into said bistable circuit and representing readable only stored information; and means for sensing the readable only stored information without changing tbe said one of two stable conditions representing the writable stored information.
Claim 14
Dependent Claim
16 words
Apparatus as in claim 10 in which the imbalancing means is connected to a word line.
Claim 15
Dependent Claim
13 words
Apparatus as in claim 10 in which the imbalancing means is a diode.
Claim 16
Dependent Claim
15 words
Apparatus as in claim 12 in which the imbalancing means is a Schottky barrier diode.
Claim 17
Dependent Claim
17 words
Apparatus as in claim 10 in which the read/write memory cell is constructed as an integrated circuit.
Claim 18
Dependent Claim
14 words
Apparatus as in claim 14 wherein said imbalancing means is connected to a substrate.
Claim 19
Dependent Claim
27 words
Apparatus as in claim 14 in which the bistable circuit adapted to be set into one of two stable conditions is connected to a bilevel power source.
Claim 20
Dependent Claim
30 words
Apparatus as in claim 10 in which said means for sensing the readable only stored information without changing the writable stored information includes means for sensing the writable stored information.
Claim 21
Dependent Claim
21 words
Apparatus as in claim 17 in which both the readable only stored information and the writable stored information are sensed simultaneously.
Claim 22
Dependent Claim
30 words
Apparatus as in claim 17 in which said sensing means compares for a dissimilarity between the condition of said bistable circuit and the latent image caused by said imbalancing means.
Claim 23
Dependent Claim
21 words
Apparatus as in claim 17 in which both the readable only stored information and the writable stored information are sensed simultaneously.
Claim 24
Dependent Claim
30 words
Apparatus as in claim 20 in which said sensing means compares for a dissimilarity between the condition of said bistable circuit and the latent image caused by said imbalancing means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-24 | 1977-12-24 | 1978-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-24 | 1981-12-24 | 1982-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-24 | 1985-12-24 | 1986-06-25 | $7700.00 | Window Closed / Lapsed |