A read/write memory having an improved write driver
Abstract
A static random-access memory is disclosed which utilizes bit line pairs for each column of memory cells for communication of data between external data terminals and the memory cells. A precharge transistor is connected between each bit line and a precharge voltage, for example Vcc, and an equilibration transistor is connected between the bit lines in each bit line pair. The precharge and equilibration transistors are controlled according to selection of the column, so that all columns which are not selected by the column address are precharged and equilibrated, including the unselected columns in the same sub-array as the selected columns. In an additional embodiment of the invention, a data transition detection circuit also controls the precharge and equilibration transistors, so that the precharge and equilibration transistors for the selected columns are turned on responsive to an input data transition during a write operation; this assists the write drivers in more quickly writing the new data onto the bit lines. Source followers are provided in the write drivers, connected to the input/output lines, to assist in the write recovery (i.e., in pulling the input/output lines high upon completion of the write operation), without requiring critical timing control. The source followers also serve to clamp the bit line voltage swing during a read, without providing a load on the bit lines during establishment of the differential voltage thereupon.

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Term ended
Projected expiry passed 11 December 2011, 14.8 years ago.
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1 sheet
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Every citation, both ways
| Document | Relation | Office | Category | Cited during |
|---|---|---|---|---|
| EP0037625A1 | Cites | European Patent Office (EPO) | A | Search report |
| EP0271283A2 | Cites | European Patent Office (EPO) | A | Search report |
| US4570243A | Cites | United States of America | X | Search report |
10 members in 5 offices
Priority claims4
| Document | Office | Kind | Date |
|---|---|---|---|
| 627059 | United States of America | – | |
| 62705990 | United States of America | A | |
| 62705990 | United States of America | A | |
| US19900627059 | – | – | – |
Members10
| Document | Office | Kind | |
|---|---|---|---|
| EP0490652A2 | European Patent Office (EPO) | A2 | |
| KR920013449A | Republic of Korea | A | |
| JPH04291093A | Japan | A | |
| EP0490652A3This record | European Patent Office (EPO) | A3 | |
| US5267197A | United States of America | A | |
| EP0490652B1 | European Patent Office (EPO) | B1 | |
| DE69128021D1 | Germany | D1 | |
| DE69128021T2 | Germany | T2 | |
| KR100228622B1 | Republic of Korea | B1 | |
| JP3322412B2 | Japan | B2 |
28 legal events, as 3 offices reported them to INPADOC
Over the term
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| Event | Code | Office | |
|---|---|---|---|
| Notification of lapseLapsedST | ST | FR | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Gb: european patent ceased through non-payment of renewal feeCeasedGBPC | GBPC | EP | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| Annual fee paid to national office [announced via postgrant information from national office to epo]GrantedPGFP | PGFP | EP | |
| Annual fee paid to national office [announced via postgrant information from national office to epo]GrantedPGFP | PGFP | EP | |
| European patent in force as of 2002-01-01IF02 | IF02 | GB | |
| Lapsed in a contracting state [announced via postgrant information from national office to epo]LapsedPG25 | PG25 | EP | |
| No opposition filedOpposition26N | 26N | EP | |
| No opposition filed within time limitOppositionORIGINAL CODE: 0009261PLBE | PLBE | EP | |
| Information on the status of an ep patent application or granted ep patentGrantedSTATUS: NO OPPOSITION FILED WITHIN TIME LIMITSTAA | STAA | EP | |
| Fr: translation filedET | ET | EP | |
| It: translation for a ep patent filedITF | ITF | EP | |
| It: translation for a ep patent filedITF | ITF | EP | |
| Annual fee paid to national office [announced via postgrant information from national office to epo]GrantedPGFP | PGFP | EP | |
| Corresponds to:REF | REF | EP | |
| Designated contracting statesAK | AK | EP | |
| (expected) grantORIGINAL CODE: 0009210GRAA | GRAA | EP | |
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| Despatch of communication of intention to grantORIGINAL CODE: EPIDOS AGRAGRAG | GRAG | EP | |
| First examination report despatched17Q | 17Q | EP | |
| Request for examination filed17P | 17P | EP | |
| Designated contracting statesAK | AK | EP | |
| Search report despatchedORIGINAL CODE: 0009013PUAL | PUAL | EP | |
| Designated contracting statesAK | AK | EP | |
| Public reference made under article 153(3) epc to a published international application that has entered the european phaseORIGINAL CODE: 0009012PUAI | PUAI | EP |
Numbers
- Publication
- 0490652
- Publication, DOCDB
- 0490652
- Publication, EPODOC
- EP0490652
- Application
- 311508
- Application, DOCDB
- 91311508
- Application, EPODOC
- EP19910311508
Titles3
- German
- Lese-/Schreibe-Speicher mit einem verbesserten Schreibtreiber
- English
- A read/write memory having an improved write driver
- French
- Une mémoire d'écriture/lecture ayant un circuit d'attaque d'écriture amélioré
Classification
- CPC, 5
- G11C7/1096
- G11C11/40
- G11C7/1048
- G11C7/1078
- G11C11/419
- IPC, 4
- G11C11 413
- G11C7 10
- G11C11 417
- G11C11 419
Designated states1
- Contracting states, 1
- Italy