Patent EP0547862A2 successfully refreshed from Google Patents.
EP0547862A2
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EP
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Semiconductor memory unit used as external storage
Assignee: Fujitsu Ltd
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Filing: 1992-12-15
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Granted: —
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Expires: 2012-12-15
Abstract
Abstract A semiconductor memory unit (12) is operated by supplying an electric power from a system power source (200v) used so as to be cut off at a predetermined time. The semiconductor memory unit (12) includes a volatile memory (14) for storing data that can be accessed by a host unit (10) coupled to the semiconductor memory unit, a battery (16) used as a back-up power source for the volatile memory (14), and a power supply controller (15), coupled to the system power source (200v), the battery (16) and an all-day service power source (100v) having a capacity less than that of the system power source (200v), for switching a power source by which electric power is supplied to the volatile memory (14) from the system power source (200v) to the all-day service power source (100v) when the system power source (200v) is cut off, and for switching it from the all-day service power source (100v) to the battery (16) when a service interruption of the all-day service power source (100v) occurs.
Inventors
- 👤 Soichiro c/o Fujitsu Limited Nagasawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 10:32
CPC Classifications
G; G06; G06F; G06F1/00; G06F1/26; G06F1/30
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
198 words
A semiconductor memory unit (2,12) operated by supplying electric power from a first power source (200V) used so as to be cut off at a predetermined time, said semiconductor memory unit comprising (2,12): volatile memory means (4,14) for storing data that can be accessed by a host unit (1) coupled to said semiconductor memory unit (2,12), said volatile memory means (4,14) maintaining the data while electric power is being supplied; and a battery (6,16) used as a back-up power source for said volatile memory means (4,14); characterized in that there is provided power supply control means (5,15), coupled to said first power source (200v), said battery (6,16) and a second power source (100v) used for performing an electric power service all day and having a capacity less than that of said first power source (200v), for switching a power source by which electric power is supplied to said volatile memory means (4,14) from said first power source (200v) to said second power source (100v) when said first power source (200v) is cut off, and for switching it from said second power source (100v) to said battery (6,16) when a service interruption of said second power source (100v) occurs.
Claim 2
Dependent Claim
198 words
A semiconductor memory unit (2,12) operated by supplying electric power from a first power source (200V) used so as to be cut off at a predetermined time, said semiconductor memory unit comprising (2,12): volatile memory means (4,14) for storing data that can be accessed by a host unit (1) coupled to said semiconductor memory unit (2,12), said volatile memory means (4,14) maintaining the data while electric power is being supplied; and a battery (6,16) used as a back-up power source for said volatile memory means (4,14); characterized in that there is provided power supply control means (5,15), coupled to said first power source (200v), said battery (6,16) and a second power source (100v) used for performing an electric power service all day and having a capacity less than that of said first power source (200v), for switching a power source by which electric power is supplied to said volatile memory means (4,14) from said first power source (200v) to said second power source (100v) when said first power source (200v) is cut off, and for switching it from said second power source (100v) to said battery (6,16) when a service interruption of said second power source (100v) occurs.
Claim 3
Dependent Claim
112 words
A semiconductor memory unit as claimed in claim 1, characterized in that said power supply control means (15) includes first detection means (50) for detecting whether or not said first power source (200v) is cut off, second detection means (51) for detecting whet her or not service interruption of said second power source (100v) occurs, and selecting means (53, 54, 55, 56, S2, S3, S4) for selecting a power source by which electric power is supplied to said volatile memory means (14) from among said first and second power sources (200v) (100v) and said battery (16) based on results obtained by said first detection means (50) and said second detection means (51).
Claim 4
Dependent Claim
50 words
A semiconductor memory unit as claimed in claim 2, characterized in that said selecting means (53, 54, 55, 56, S2, S3, S4) includes first means (S2) for selecting said first power source (200v) when said first detection means (50) detects that said first power source (200v) is not cut off.
Claim 5
Dependent Claim
51 words
A semiconductor memory unit as claimed in claim 3, characterized in that said selecting means (53, 54, 55, 56, S2, S3, S4) includes second means (53, 55, S3) for selecting said second power source (100v) when said first detection means (50) detects that said first power source (200v) is cut off.
Claim 6
Dependent Claim
67 words
A semiconductor memory unit as claimed in claim 4, characterized in that said selecting means (53, 54, 55, 56, S2, S3, S4) includes third means (53, 54, 56, S4) for selecting said battery (16) when said first detection means (50) detects that said first power source (200v) is cut off and said second detection means (51) detects that service interruption of said second power source (100v) occurs.
Claim 7
Dependent Claim
40 words
A semiconductor memory unit as claimed in claim 1, characterized in that said semiconductor memory unit (2) is a semiconductor disk unit in which data is stored in said volatile memory means (14) in accordance with a magnetic disk format.
Claim 8
Dependent Claim
19 words
Asemiconductor memory unit as claimed in claim 1, characterized in that said battery (16) is a secondary battery, rechargeable.
Claim 9
Dependent Claim
35 words
Asemiconductor memory unit as claimed in claim 1, characterized in that an all-day service power source supplying electric power to other equipments to be activated all day is used as said second power source (100v).
References Cited (Backward Citations)
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