US4168490A
Expired / Lapsed
US
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Addressable word line pull-down circuit
Assignee: National Semiconductor Corp
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Filing: 1978-06-26
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Granted: 1979-09-18
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Expires: 1998-06-26
Abstract
Abstract Computer circuitry for rapidly discharging the deselected word lines in high-speed very low power random access memories that may be accidentally triggered by noise pulses if permitted to decay at the normal rate.
Inventors
- 👤 Jonathan J. Stinehelfer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:49
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/41; G11C11/413; G11C11/414; G11C11/415
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
75 words
Word line pull-down circuitry for rapidly discharging a deselected word line of a random access memory, said circuitry comprising: a transistor switch coupled between the word line and ground reference; and control circuitry responsive to the selection of said word line and coupled to said switch for maintaining said switch in a conductive state during the period of said selection and thereafter during an interval required for discharging said word line to its low state.
Claim 2
Dependent Claim
75 words
Word line pull-down circuitry for rapidly discharging a deselected word line of a random access memory, said circuitry comprising: a transistor switch coupled between the word line and ground reference; and control circuitry responsive to the selection of said word line and coupled to said switch for maintaining said switch in a conductive state during the period of said selection and thereafter during an interval required for discharging said word line to its low state.
Claim 3
Dependent Claim
28 words
The circuitry claimed in claim 1 wherein said control circuit is coupled to the output of a word line decoder and is responsive to the selection signal therefrom.
Claim 4
Dependent Claim
18 words
The circuitry claimed in claim 1 wherein said transistor switch is coupled to ground reference through a resistance.
Claim 5
Dependent Claim
55 words
The circuitry claimed in claim 3 wherein said control circuit is coupled between said word line and ground reference and includes a capacitor that is charged during said period of word line selection and, upon deselection of said word line discharges to provide base drive current to maintain said transistor switch in a conductive state.
Claim 6
Dependent Claim
78 words
The circuitry claimed in claim 3 wherein said control circuitry comprises a flip-flop circuit that is set by the signal from the upper word line interconnecting the output of a word line decoder with the memory cells and is reset by the signal on a lower word line intercoupling said cells to ground reference through said pull-down circuitry, the true output of said flip-flop controlling said transistor switch coupled between said lower word line and said ground reference.
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) | 1982-09-17 | 1983-03-19 | 1983-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-09-17 | 1987-03-19 | 1987-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-09-17 | 1991-03-19 | 1991-09-18 | $7700.00 | Window Closed / Lapsed |