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:
Dec. 22, 2009
Filed:
Mar. 03, 2004
Applicants:
Satoru Akiyama, Kokubunji, JP;
Takeshi Sakata, Hino, JP;
Takao Watanabe, Fuchu, JP;
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
G06F 12/08 (2006.01); G11C 8/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A semiconductor device employs a SESO memory or a phase change memory which has a smaller memory cell area than SRAM. The semiconductor device has a plurality of memory banks each composed of the SESO or phase change memories, and a cache memory which has a number of ways equal to the ratio of a write speed (m) to a read speed (n). The semiconductor device controls the cache memory such that a write back operation is not repeated on the same memory bank.