US4802166A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for the verification of memory cells on the basis of the threshold drop obtainable during writing
Assignee: STMicroelectronics SRL
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Filing: 1986-02-28
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Granted: 1989-01-31
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Expires: 2006-02-28
Abstract
Abstract A comparator has two inputs, one controlled by a circuit branch including a written cell being examined and one controlled by another circuit branch including a virgin cell. In parallel with the latter is placed another reference cell controlled in an adjustable manner in such a way as to raise the threshold of the written cell which the device is able to discriminate and accept.
Inventors
- 👤 Giulio Casagrande
- 👤 Roberto Gastaldi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:30
CPC Classifications
G; G11; G11C; G11C16/00; G11C16/02; G11C16/06; G11C16/34; G11C16/3436; G11C16/3454; G11C16/3459; G11C29/00; G11C29/04; G11C29/50; G11C29/50004; G06; G06F; G06F2201/00; G06F2201/81; G11C16/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
75 words
A device for verification of a memory cell under examination on the basis of a threshold drop obtainable in the writing phase of said memory cell under examination, comprising: a comparator with two controlled inputs, one from a circuit branch including said cell under examination and another from another circuit branch, said another circuit branch including a virgin cell, and a reference cell in parallel with said virgin cell and controlled in an adjustable manner.
Claim 2
Independent Claim
75 words
A device for verification of a memory cell under examination on the basis of a threshold drop obtainable in the writing phase of said memory cell under examination, comprising: a comparator with two controlled inputs, one from a circuit branch including said cell under examination and another from another circuit branch, said another circuit branch including a virgin cell, and a reference cell in parallel with said virgin cell and controlled in an adjustable manner.
Claim 3
Dependent Claim
50 words
A device in accordance with claim 1 further comprising a voltage generator, wherein said cell under examination is driven by a control voltage, and said reference cell is controllable through said voltage generator, said voltage generator having a voltage value lower than the control voltage of the cell under examination.
Claim 4
Dependent Claim
43 words
A device in accordance with claim 1 further comprising a variable voltage generator, wherein said reference cell is further controllable through said variable voltage generator which makes it possible to measure a threshold drop produced by the writing of the cell under examination.
Claim 5
Dependent Claim
65 words
A device in accordance with claim 1 further comprising: a voltage generator, wherein said cell under examination is driven by a control voltage, and said reference cell is controllable through said voltage generator, said voltage generator having a voltage value lower than the control voltage of the cell under examination; and a variable voltage generator which makes it possible to variably control said reference cell.
Claim 6
Dependent Claim
24 words
A device in accordance with claim 4 further comprising means for selecting one or the other of said generators for controlling said reference cell.
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) | 1992-01-31 | 1992-08-01 | 1993-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-31 | 1996-08-01 | 1997-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-31 | 2000-08-01 | 2001-01-31 | $7700.00 | Window Closed / Lapsed |