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US5075888A
Expired / Lapsed
US
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Semiconductor memory device having a volatile memory device and a non-volatile memory device
Assignee: Sharp Corp
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Filing: 1989-02-09
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Granted: 1991-12-24
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Expires: 2009-02-09
Abstract
Abstract A semiconductor memory device composed of a DRAM, an EEPROM, a mode switch means for selecting either mode of the DRAM mode and the EEPROM mode, and a transfer means for transferring data stored in the DRAM to the EEPROM and vice versa. The DRAM consists of one transistor and one capacitor, and one of the terminals of the capacitor is electrically isolated.
Inventors
- 👤 Yoshimitsu Yamauchi
- 👤 Kenichi Tanaka
- 👤 Keizo Sakiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:11
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/005; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/403; G11C11/404; G11C14/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
120 words
In a semiconductor memory device comprising: volatile memory means; a non-volatile memory means; a mode switch means for selecting either mode of a volatile memory mode in which said memory device functions as a volatile memory device and a non-volatile memory mode in which said memory device functions as a non-volatile memory device; and a transfer means for transferring data stored in said volatile memory means to said non-volatile memory means, the improvement existing in that said volatile memory means consists of one transistor and one capacitor, and one of the terminals of said capacitor is electrically isolated from said non-volatile memory means and electrically coupled to a terminal to which one of a plurality of predetermined voltages is applied.
Claim 2
Dependent Claim
120 words
In a semiconductor memory device comprising: volatile memory means; a non-volatile memory means; a mode switch means for selecting either mode of a volatile memory mode in which said memory device functions as a volatile memory device and a non-volatile memory mode in which said memory device functions as a non-volatile memory device; and a transfer means for transferring data stored in said volatile memory means to said non-volatile memory means, the improvement existing in that said volatile memory means consists of one transistor and one capacitor, and one of the terminals of said capacitor is electrically isolated from said non-volatile memory means and electrically coupled to a terminal to which one of a plurality of predetermined voltages is applied.
Claim 3
Dependent Claim
120 words
In a semiconductor memory device comprising: a volatile memory means; a non-volatile memory means; a mode switch means for selecting either mode of a volatile memory mode in which said memory device functions as a volatile memory device and a non-volatile memory mode in which said memory device functions as a non-volatile memory device; and a transfer means for transferring data stored in said non-volatile memory means to said volatile memory means, the improvement existing in that said volatile means consists of one transistor and one capacitor, and one of the terminals of said capacitor is electrically isolated from said non-volatile memory means and electrically coupled to a terminal to which one of a plurality of predetermined voltages is applied.
Claim 4
Dependent Claim
120 words
In a semiconductor memory device comprising: a volatile memory means; a non-volatile memory means; a mode switch means for selecting either mode of a volatile memory mode in which said memory device functions as a volatile memory device and a non-volatile memory mode in which said memory device functions as a non-volatile memory device; and a transfer means for transferring data stored in said non-volatile memory means to said volatile memory means, the improvement existing in that said volatile means consists of one transistor and one capacitor, and one of the terminals of said capacitor is electrically isolated from said non-volatile memory means and electrically coupled to a terminal to which one of a plurality of predetermined voltages is applied.
Claim 5
Dependent Claim
135 words
In a semiconductor memory device comprising: a volatile memory means; a non-volatile memory means; a mode switch means for selecting either mode of a volatile memory mode in which said memory device functions as a volatile memory device and a non-volatile memory mode in which said memory device functions as a non-volatile memory device; and a transfer means for transferring data stored in said volatile memory means to said non-volatile memory means and for transferring data stored in said non-volatile memory means to said volatile memory means, the improvement existing in that said volatile means consists of one transistor and one capacitor, and one of the terminals of said capacitor is electrically isolated from said non-volatile memory means and electrically coupled to a terminal to which one of a plurality of predetermined voltages is applied.
Claim 6
Dependent Claim
135 words
In a semiconductor memory device comprising: a volatile memory means; a non-volatile memory means; a mode switch means for selecting either mode of a volatile memory mode in which said memory device functions as a volatile memory device and a non-volatile memory mode in which said memory device functions as a non-volatile memory device; and a transfer means for transferring data stored in said volatile memory means to said non-volatile memory means and for transferring data stored in said non-volatile memory means to said volatile memory means, the improvement existing in that said volatile means consists of one transistor and one capacitor, and one of the terminals of said capacitor is electrically isolated from said non-volatile memory means and electrically coupled to a terminal to which one of a plurality of predetermined voltages is applied.
Claim 7
Dependent Claim
134 words
In a semiconductor memory device comprising: a volatile memory means; a non-volatile memory means; a mode switch means for selecting either mode of a volatile memory mode in which said memory device functions as a volatile memory device and a non-volatile memory mode in which said memory device functions as a non-volatile memory device; and a transfer means for transferring data between said volatile memory means and said non-volatile memory means in accordance with the mode selected by said switch means, the improvement existing in that said volatile memory means consists of one transistor and one capacitor, and an isolation means for electrically isolating said non volatile memory means from said volatile memory means is disposed therebetween and electrically coupled to a terminal to which one of a plurality of predetermined voltages is applied.
Claim 8
Dependent Claim
134 words
In a semiconductor memory device comprising: a volatile memory means; a non-volatile memory means; a mode switch means for selecting either mode of a volatile memory mode in which said memory device functions as a volatile memory device and a non-volatile memory mode in which said memory device functions as a non-volatile memory device; and a transfer means for transferring data between said volatile memory means and said non-volatile memory means in accordance with the mode selected by said switch means, the improvement existing in that said volatile memory means consists of one transistor and one capacitor, and an isolation means for electrically isolating said non volatile memory means from said volatile memory means is disposed therebetween and electrically coupled to a terminal to which one of a plurality of predetermined voltages is applied.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-23 | 1995-06-24 | 1995-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-23 | 1999-06-24 | 1999-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-23 | 2003-06-24 | 2003-12-24 | $7700.00 | Window Closed / Lapsed |