US6366515B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor memory device
Assignee: Mitsubishi Electric Corp
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Filing: 2000-12-18
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Granted: 2002-04-02
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Expires: 2020-12-18
Abstract
Abstract A refresh address is set to a definite state prior to the rise of a clock signal, a refresh instruction is taken-in in synchronization with a clock signal and a refresh operation is performed according to the refresh instruction. Further, in a refresh operation, refresh is performed with a sub-word line being a unit; thereby enabling high speed refresh of memory sell data with a reduced current consumption.
Inventors
- 👤 Hideto Hidaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:37
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/406
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
105 words
A semiconductor memory device operating in synchronization with a clock signal, comprising: a refresh address generating circuit for generating a refresh address specifying a memory cell to be refreshed in a refresh mode for performing a refreshing of storage data to restore the storage data; an address circuit generating an internal address based on said refresh address asynchronously with said clock signal; and a refresh control circuit taking in an externally supplied refresh instruction in synchronization with said clock signal and generating a refresh control signal for performing the refreshing of a memory cell specified by said internal address according to the taken-in refresh instruction.
Claim 2
Dependent Claim
105 words
A semiconductor memory device operating in synchronization with a clock signal, comprising: a refresh address generating circuit for generating a refresh address specifying a memory cell to be refreshed in a refresh mode for performing a refreshing of storage data to restore the storage data; an address circuit generating an internal address based on said refresh address asynchronously with said clock signal; and a refresh control circuit taking in an externally supplied refresh instruction in synchronization with said clock signal and generating a refresh control signal for performing the refreshing of a memory cell specified by said internal address according to the taken-in refresh instruction.
Claim 3
Dependent Claim
76 words
The semiconductor memory device according to claim 1 , further comprising: an address selection circuit for selecting one of an address signal supplied externally and said refresh address according to an operating mode instructing signal to supply a selected one to said address circuit asynchronously with said clock signal, said address selection circuit selecting said refresh address when said operating mode instructing signal specifies said refresh mode to supply said refresh address to said address circuit.
Claim 4
Dependent Claim
47 words
The semiconductor memory device according to claim 2 , further comprising: row-related circuitry operating in synchronization with said clock signal, for driving a row including a memory cell addressed by the internal address signal generated from said address circuit in accordance with said operating mode instructing signal.
Claim 5
Dependent Claim
46 words
The semiconductor memory device according to claim 1 , further comprising: a spare determination circuit storing an address of a defective memory cell and operating asynchronously with said clock signal to determine whether the internal address generated from said address circuit specifies said defective memory 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) | 2005-04-01 | 2005-10-01 | 2006-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-04-01 | 2009-10-01 | 2010-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-04-01 | 2013-10-01 | 2014-04-02 | $7700.00 | Window Closed / Lapsed |