Patent US4223395A successfully refreshed from Google Patents.
US4223395A
Expired / Lapsed
US
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Volatile memory hold device
Assignee: Omron Corp
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Filing: 1978-10-16
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Granted: 1980-09-16
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Expires: 1998-10-16
Abstract
Abstract A volatile memory hold device comprising power terminals to which a power source is connectable, a volatile memory connected to the power terminals which serves as input power terminals therefor, and a charge-and-discharge circuit connected to the power terminal in parallel with the memory, the charge-and-discharge circuit including a capacitor which is charged by the power for the volatile memory and to supply the memory with the power discharged therefrom, whereby the memory retains stored data even when power supplied from the power source is no longer available.
Inventors
- 👤 Shunichi Sakaguchi
- 👤 Kiyohide Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:59
CPC Classifications
G; G11; G11C; G11C5/00; G11C5/14; G11C5/141
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
130 words
A volatile memory hold device comprising power terminals to which a power source is connectable, a volatile memory connected to said power terminals, the latter serving as input power terminals for said volatile memory, and a charge-and-discharge circuit connected across said power terminals in parallel with said memory, said charge-and-discharge circuit including a capacitor and a first resistor connected in series with said capacitor, said capacitor being charged by power for said volatile memory supplied over said power terminals and supplying said memory with power discharged therefrom, said resistor having a resistance value which prevents application of a rush current to said memory from said capacitor, said charge-and discharge circuit enabling said memory to retain stored data even when the power supply from said power source is no longer available.
Claim 2
Dependent Claim
130 words
A volatile memory hold device comprising power terminals to which a power source is connectable, a volatile memory connected to said power terminals, the latter serving as input power terminals for said volatile memory, and a charge-and-discharge circuit connected across said power terminals in parallel with said memory, said charge-and-discharge circuit including a capacitor and a first resistor connected in series with said capacitor, said capacitor being charged by power for said volatile memory supplied over said power terminals and supplying said memory with power discharged therefrom, said resistor having a resistance value which prevents application of a rush current to said memory from said capacitor, said charge-and discharge circuit enabling said memory to retain stored data even when the power supply from said power source is no longer available.
Claim 3
Dependent Claim
44 words
A volatile memory hold device according to claim 1 further comprising first diode for blocking the flow of a current from said charge-and-discharge circuit to said power terminals, said memory and said charge-and-discharge circuit being connected through said first diode across said power terminals.
Claim 4
Dependent Claim
67 words
A volatile memory hold device according to claim 1 further comprising a supplemental power source circuit having a battery, the discharge power of which is applied to said memory when no power is available from said power source to said power terminals, said capacitor supplying said memory with its discharge power when no power is available from either said power source or said supplemental power source circuit.
Claim 5
Dependent Claim
23 words
A volatile memory hold device according to claim 3, wherein said battery is a rechargeable battery which is charged by said power source.
Claim 6
Dependent Claim
38 words
A volatile memory hold device according to claim 3, wherein said supplemental power source further comprises a second diode for blocking the flow of a current from said power source to said battery and said battery is nonrechargeable.
Claim 7
Dependent Claim
30 words
A volatile memory hold device according to claim 3 further comprising a third diode for blocking the flow of a current from said charge-and-discharge circuit to said supplemental power source.
Claim 8
Dependent Claim
32 words
A volatile memory hold device according to claim 1 further comprising a display for indicating that the power supplied to said memory is below a minimum operational power for said volatile memory.
Claim 9
Dependent Claim
98 words
A volatile memory hold device according to claim 1 further comprising a Zener diode and a third resistor, said memory being connected in parallel with said Zener diode and through said third resistor to one of said power terminals, the Zener voltage of said Zener diode being less than a maximum allowable supply voltage of said memory, said capacitor being charged by said power source to a voltage which maintains said memory in an operational region even when the exponential slope of the discharge voltage supplied to said memory from said capacitor flattens after said capacitor starts discharging.
Claim 10
Dependent Claim
17 words
A volatile memory hold device according to claim 1, wherein said volatile memory is a C-MOS RAM.
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) | 1983-09-16 | 1984-03-17 | 1984-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-16 | 1988-03-17 | 1988-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-16 | 1992-03-17 | 1992-09-16 | $7700.00 | Window Closed / Lapsed |