DocumentCode :
3294685
Title :
Fault-tolerant refresh power reduction of DRAMs for quasi-nonvolatile data retention
Author :
Katayama, Yasunao ; Stuckey, Eric J. ; Morioka, Sumio ; Wu, Zhao
Author_Institution :
Tokyo Res. Lab., IBM Res., Kanagawa, Japan
fYear :
1999
fDate :
36465
Firstpage :
311
Lastpage :
318
Abstract :
A quasi-nonvolatile memory system based on commercially available low-power dynamic random access memory (DRAM) technology is proposed and demonstrated. By applying a powerful one-shot Reed-Solomon error correction code (ECC) to the data stored in the DRAM, the refresh rate and memory system power usage can be greatly reduced while still maintaining data integrity. An adaptive refresh rate controller was developed in order to ensure robustness against the variations in data retention time due to perturbation effects such as DRAM part-to-part variations, environmental changes and data pattern sensitivity, while at the same time minimizing power usage. By checking for data failures among a small subset of data bits which are dynamically selected at the beginning of each use of the system, the state of the perturbation effects are predicted and used to adjust the refresh rate. As a result, a system was developed that provides reliability equivalent to standard DRAM systems while greatly (10-100X) reducing the refresh power. Experimental results of a test system are presented
Keywords :
DRAM chips; Reed-Solomon codes; error correction codes; fault tolerance; DRAMs; adaptive refresh rate controller; data integrity; data pattern sensitivity; fault-tolerant refresh power reduction; memory system power usage; one-shot Reed-Solomon error correction code; part-to-part variations; perturbation effects; quasi-nonvolatile data retention; Adaptive control; DRAM chips; Error correction codes; Fault tolerance; Power system reliability; Programmable control; Random access memory; Reed-Solomon codes; Robust control; Standards development;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Defect and Fault Tolerance in VLSI Systems, 1999. DFT '99. International Symposium on
Conference_Location :
Albuquerque, NM
ISSN :
1550-5774
Print_ISBN :
0-7695-0325-x
Type :
conf
DOI :
10.1109/DFTVS.1999.802898
Filename :
802898
Link To Document :
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