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US5646903A
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Memory cell having a shared read/write line
Assignee: Xilinx Inc
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Filing: 1996-03-06
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Granted: 1997-07-08
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Expires: 2016-03-06
Abstract
Abstract A DRAM memory having shared read/write lines. The DRAM memory is comprised of an array of 3T memory cells. Data is digitally stored in the form of capacitors that are either charged or discharged. Horizontal data lines are used to convey data bits to be stored in the array of memory cells. Vertical read/write lines are used to perform both read and write functions. Activating a single read/write line causes a bit of data from a memory cell to be placed onto a corresponding data line. Simultaneously, an inverted copy of that data bit is stored in an adjacent memory cell. Hence, instead of having a separate read line and a separate word line for each memory cell, the present invention has a dual function read/write word line.
Inventors
- 👤 R. Anders Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:30
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/403; G11C11/405; G11C8/00; G11C8/16
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
115 words
A memory for storing digital data comprising: a first memory cell for storing a first bit of information; a second memory cell for storing a second bit of information; a data line coupled to the first memory cell and the second memory cell for conducting the first bit of information and the second bit of information, wherein said data line transfers said first bit of information into said second memory cell; and a control line coupled to the first memory cell and the second memory cell, wherein activating the control line causes a read operation to be performed on the first memory cell and a write operation to be performed on the second memory cell.
Claim 2
Dependent Claim
115 words
A memory for storing digital data comprising: a first memory cell for storing a first bit of information; a second memory cell for storing a second bit of information; a data line coupled to the first memory cell and the second memory cell for conducting the first bit of information and the second bit of information, wherein said data line transfers said first bit of information into said second memory cell; and a control line coupled to the first memory cell and the second memory cell, wherein activating the control line causes a read operation to be performed on the first memory cell and a write operation to be performed on the second memory cell.
Claim 3
Dependent Claim
131 words
The memory of claim 1, wherein the first memory cell is comprised of: a first transistor coupled to the data line for controlling when the first memory cell is to be written; a second transistor coupled to the data line for controlling when the first memory cell is to be read; a storage node coupled to the first transistor for storing the bit of information according to a high or low voltage of the storage node; a third transistor coupled to the second transistor and the storage node for providing a signal path from the the storage node through the second transistor to the data line; and a capacitor coupled to said storage node, wherein said capacitor may consist of the parasitic capacitance of said third transistor or said first transistor.
Claim 4
Dependent Claim
40 words
The memory of claim 1, wherein activating the control line causes the first bit to be read from the first memory cell and an inverted copy of the first bit of information to be written to the second memory cell.
Claim 5
Dependent Claim
31 words
The memory of claim 2 further comprising a circuit for clearing the memory after power is applied to the memory by pulling all data lines low while activating all read/write lines.
Claim 6
Dependent Claim
10 words
The memory of claim 1, wherein data is read sequentially.
Claim 7
Dependent Claim
21 words
The memory of claim 1, wherein the first memory cell and the second memory cell are comprised of 3T DRAM cells.
Claim 8
Dependent Claim
22 words
The memory of claim 3 wherein a row of memory cells indicates whether or not the data in each column is inverted.
Claim 9
Dependent Claim
15 words
The memory of claim 1 wherein a counter is used for selecting said control line.
Claim 10
Dependent Claim
12 words
The memory of claim 8 wherein said counter is a ring counter.
Claim 11
Dependent Claim
19 words
The memory of claim 3 wherein an XOR gate is used to restore inverted data to its original polarity.
Claim 12
Dependent Claim
100 words
A DRAM memory comprising: an array of 3T memory cells; a plurality of data lines coupled to the memory cells, wherein the data is written to the memory cells and read from the memory cells through the data lines; a plurality of read/write lines coupled to the memory cells, wherein activating one of the read/write lines causes a bit stored in a first memory cell coupled to the read/write line to be conducted to one of the data lines and an inverted copy of the bit to be stored in a second memory cell also coupled to the read/write line.
Claim 13
Dependent Claim
100 words
A DRAM memory comprising: an array of 3T memory cells; a plurality of data lines coupled to the memory cells, wherein the data is written to the memory cells and read from the memory cells through the data lines; a plurality of read/write lines coupled to the memory cells, wherein activating one of the read/write lines causes a bit stored in a first memory cell coupled to the read/write line to be conducted to one of the data lines and an inverted copy of the bit to be stored in a second memory cell also coupled to the read/write line.
Claim 14
Dependent Claim
22 words
The DRAM memory of claim 11, wherein a signal is applied to both a left-most read/write line and a right-most read/write line.
Claim 15
Dependent Claim
131 words
The DRAM memory of claim 11, wherein one of the memory cells is comprised of: a first transistor coupled to a particular data line for controlling when the memory cell is to be written; a second transistor coupled to the particular data line for controlling when the memory cell is to be read; a storage node coupled to the first transistor for storing a bit according to a high or low voltage of the storage node; a third transistor coupled to the second transistor and the storage node for providing a signal path from the storage node through the second transistor to the particular data line; and a capacitor coupled to said storage node, wherein said capacitor may consist of the parasitic capacitance of said third transistor or said first transistor.
Claim 16
Independent Claim
116 words
A method for accessing digital data stored in a memory, comprising the steps of: clearing a first memory cell, a second memory cell, and a third memory cell; placing a first bit of information on a data line; activating a first control line to write the first bit of information to the first memory cell; placing a second bit of information on the data line; activating a second control line to write the second bit of information to the second memory cell; activating a third control line to read the first memory cell, wherein activating the third control line also simultaneously writes an inverted copy of the first bit of information to the third memory cell.
Claim 17
Independent Claim
116 words
A method for accessing digital data stored in a memory, comprising the steps of: clearing a first memory cell, a second memory cell, and a third memory cell; placing a first bit of information on a data line; activating a first control line to write the first bit of information to the first memory cell; placing a second bit of information on the data line; activating a second control line to write the second bit of information to the second memory cell; activating a third control line to read the first memory cell, wherein activating the third control line also simultaneously writes an inverted copy of the first bit of information to the third memory cell.
Claim 18
Dependent Claim
33 words
The method of claim 14 further comprising the step of changing the output polarity for every N read operations, wherein N is a number of columns of bits of information in the memory.
Claim 19
Dependent Claim
17 words
The method of claim 14 further comprising the step of sequentially reading data from the memory cells.
Claim 20
Dependent Claim
25 words
The method of claim 14 further comprising the step of transmitting a same signal to a left-most control line and to a right-most control line.
References Cited (Backward Citations)
US4935896A
Cited
US5513139A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-07 | 2001-01-06 | 2001-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-07 | 2005-01-06 | 2005-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-07 | 2009-01-06 | 2009-07-08 | $7700.00 | Window Closed / Lapsed |