Dynamic random access memory with operational sleep mode
US5262998A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 14, 1991 |
| Grant date | Nov 16, 1993 |
| Priority date | — |
| Expiry date | Aug 14, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C11/406
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A dynamic memory device exhibits a sleep mode of operation, entered in response to a single externally-applied signal which need not be cycled. While in this sleep mode, the device does not respond to or require any of the usual DRAM control signals such a RAS, CAS, write enable, address inputs, data inputs, etc., so all of these signals may be in a quiescent state. An internal refresh counter is used to generate row addresses while in the sleep mode, and timing for the internal refresh is provided by an internal oscillator. The memory device cycles through a sequence of row addresses for refresh while in this sleep mode, using an internal refresh address counter, and this sequence may be maintained without interruption if the sleep mode is reentered within a normal refresh period after exiting the sleep mode. Thus, a sleep-exception mode of operation is provided in which normal read or write cycles can be interposed between sleep mode periods, so the overall power drain is very low but normal access is maintained at a relatively active level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.