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US5140557A
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Static random access memory of an energy-saving type
Assignee: Sharp Corp
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Filing: 1990-09-11
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Granted: 1992-08-18
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Expires: 2010-09-11
Abstract
Abstract In a static random access memory for storing data in a plurality of memory cells constituting a memory cell array to which a specified electric current for activating each memory cell is supplied from a power source via a path, a P-channel MOSFET is provided as a switch on the path between the power source and the memory cell array. When reading or writing of data in memory cells is performed, the switch is turned on and a specified electric current for activating the memory cells is supplied to the memory cell via the path having the switch. Between the power source and the memory cell array is also provided an electric resistor connected in parallel with the switch. During a stand-by state of the memory cell array, the switch is turned off so that the above path is cut off, and a voltage of the power source is applied through the resistor to the memory cells. Consequently, the electric current supplied to the memory cells becomes smaller than when the electric current flows via the above path, whereby consumption of electricity is suppressed.
Inventors
- 👤 Makoto Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:10
CPC Classifications
G; G11; G11C; G11C5/00; G11C5/14; G11C5/147; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/41; G11C11/413; G11C11/417
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
130 words
A static random access memory for storing data in a plurality of memory cells constituting a memory cell array to which a predetermined electric current is supplied from a power source via a path, comprising: switch means provided on the path between the power source and the memory cell array for enabling cut-off of the path when the memory is in a stand-by state; and an electric resistor connected between the power source and the memory cell array in parallel with said switch means and adjusted to a predetermined value for decreasing an electric current supplied to the memory cells to a minimum for holding data in the memory cells; whereby when the path is cut off, the electric current flows to the memory cell array via said electric resistor.
Claim 2
Dependent Claim
130 words
A static random access memory for storing data in a plurality of memory cells constituting a memory cell array to which a predetermined electric current is supplied from a power source via a path, comprising: switch means provided on the path between the power source and the memory cell array for enabling cut-off of the path when the memory is in a stand-by state; and an electric resistor connected between the power source and the memory cell array in parallel with said switch means and adjusted to a predetermined value for decreasing an electric current supplied to the memory cells to a minimum for holding data in the memory cells; whereby when the path is cut off, the electric current flows to the memory cell array via said electric resistor.
Claim 3
Dependent Claim
74 words
The static random access memory as claimed in claim 1, wherein said switch means comprises a P-channel metal oxide semiconductor field effect transistor, and when the memory cell array is required to be activated, a ground potential is applied to a gate electrode of the P-channel metal oxide semiconductor field effect transistor and when the memory cell array is not required to be activated, a power source potential is applied to the gate electrode.
Claim 4
Dependent Claim
165 words
A static random access memory for storing data in a plurality of memory cells constituting a memory cell array to which a predetermined electric current is supplied from a power source via a path comprising: switch means provided on the path between the power source and the memory cell array for enabling cut-off of the path when the memory is in a stand-by state, said switch means comprises a P-channel metal oxide semiconductor field effect transistor, and when the memory cell array is required to be activated, a ground potential is applied to a gate electrode of the P-channel metal oxide semiconductor field effect transistor and when the memory cell array fails to be activated, a power source potential is applied to the gate electrode; and an electric resistor connected between the power source and the memory cell array in parallel with said switch means; whereby when the path is cut off, the electric current flows to the memory cell array via said electric resistor.
Claim 5
Dependent Claim
165 words
A static random access memory for storing data in a plurality of memory cells constituting a memory cell array to which a predetermined electric current is supplied from a power source via a path comprising: switch means provided on the path between the power source and the memory cell array for enabling cut-off of the path when the memory is in a stand-by state, said switch means comprises a P-channel metal oxide semiconductor field effect transistor, and when the memory cell array is required to be activated, a ground potential is applied to a gate electrode of the P-channel metal oxide semiconductor field effect transistor and when the memory cell array fails to be activated, a power source potential is applied to the gate electrode; and an electric resistor connected between the power source and the memory cell array in parallel with said switch means; whereby when the path is cut off, the electric current flows to the memory cell array via said electric resistor.
References Cited (Backward Citations)
US4482985A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-08-18 | 1996-02-17 | 1996-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-18 | 2000-02-17 | 2000-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-18 | 2004-02-17 | 2004-08-18 | $7700.00 | Window Closed / Lapsed |