US4787066A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-volatile shadow storage cell with improved level shifting circuit and reduced tunnel device count for improved reliability
Assignee: STMicroelectronics lnc USA
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Filing: 1987-08-03
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Granted: 1988-11-22
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Expires: 2007-08-03
Abstract
Abstract A non-volatile storage cell utilizing improved level shifting circuitry to charge and discharge at least a single isolation device, preferably of the Fowler-Nordheim tunneling type, wherein such level shifting input/output circuit is fully static providing for the elimination of any requirement for a gate booster capacitor and allows the high voltage source to replace any long term charge loss. The use of silicon area is reduced.
Inventors
- 👤 Horst Leuschner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:39
CPC Classifications
G; G11; G11C; G11C14/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
224 words
In a non-volatile shadow memory cell comprising a non-volatile storage element and at least one isolation element for charging and discharging the at least one non-volatile storage element, the improvement comprising in combination: level shifting means for charging and discharging the non-volatile storage element, said level shifting means for charging and discharging the non-volatile storage element further comprising: a latching circuit, said latching circuit having a first and a second input drive terminal, one of said first and second input terminals also being an output terminal; a coupling capacitor, said coupling capacitor being connected from said output terminal of said latching circuit to a control electrode of the nonvolatile storage element; a first drive transistor, said first drive transistor having a gate electrode connected to a first logic signal source; a second drive transistor, said second drive transistor having a gate electrode connected to a second logic signal source, said first and said second logic signal sources being complementary each to the other; said first drive transistor having a first electrode connected to said first input terminal of said latching circuit, and said first drive transistor having a second electrode connected to ground; and said second drive transistor having a first electrode connected to said second input terminal of said latching circuit, and said second drive transistor having a second electrode connected to ground.
Claim 2
Dependent Claim
224 words
In a non-volatile shadow memory cell comprising a non-volatile storage element and at least one isolation element for charging and discharging the at least one non-volatile storage element, the improvement comprising in combination: level shifting means for charging and discharging the non-volatile storage element, said level shifting means for charging and discharging the non-volatile storage element further comprising: a latching circuit, said latching circuit having a first and a second input drive terminal, one of said first and second input terminals also being an output terminal; a coupling capacitor, said coupling capacitor being connected from said output terminal of said latching circuit to a control electrode of the nonvolatile storage element; a first drive transistor, said first drive transistor having a gate electrode connected to a first logic signal source; a second drive transistor, said second drive transistor having a gate electrode connected to a second logic signal source, said first and said second logic signal sources being complementary each to the other; said first drive transistor having a first electrode connected to said first input terminal of said latching circuit, and said first drive transistor having a second electrode connected to ground; and said second drive transistor having a first electrode connected to said second input terminal of said latching circuit, and said second drive transistor having a second electrode connected to ground.
Claim 3
Dependent Claim
27 words
The improvement in a non-volatile shadow memory cell in accordance with claim 1 wherein the at least one isolation element comprises: at least one Fowler-Nordheim tunneling element.
Claim 4
Dependent Claim
45 words
The improvement in non-volatile shadow memory cell in accordance with claim 1 wherein said at least one isolation element for charging and discharging the at least one non-volatile storage element comprises a single isolation element adapted for providing both said charging and said discharging current.
Claim 5
Dependent Claim
35 words
The improvement in a non-volatile shadow memory cell in accordance with claim 2 wherein said means for charging and discharging comprise a single isolation element adapted for providing both said charging and said discharging current.
References Cited (Backward Citations)
US4510584A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |