The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 24, 2004
Filed:
Aug. 08, 2001
Applicant:
Inventors:
Yutaka Ito, Ome, JP;
Hidetoshi Iwai, Fussa, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11C 2/900 ; G11C 7/00 ; G06F 1/100 ; G11B 5/09 ;
U.S. Cl.
CPC ...
G11C 2/900 ; G11C 7/00 ; G06F 1/100 ; G11B 5/09 ;
Abstract
When a DRAM enters an operation mode in which only a data storing operation is performed, a check bit for error detection and correction for plural data is generated and stored. Refresh operation is performed in a refresh cycle which is made long within an allowable range of an error occurrence by an error correcting operation using the check bit. Before the DRAM returns to the normal operation mode from the data holding operation mode, an error bit is corrected by using the data and the check bit.