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:
Oct. 28, 2003
Filed:
Feb. 03, 2003
Applicant:
Inventors:
Satoshi Takahashi, Kawasaki, JP;
Minoru Yamashita, Kawasaki, JP;
Assignee:
Fujitsu Limited, Kawasaki, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11C 1/604 ;
U.S. Cl.
CPC ...
G11C 1/604 ;
Abstract
In a nonvolatile semiconductor memory device, first and second dynamic reference cells are subjected to a same rewriting operation as performed to a memory cell. An average reference current is obtained from the first and second dynamic reference cells, and is compared with a current of data read from the memory cell so as to judge a level of the read data. In this configuration, the second dynamic reference cell is programmed according to a threshold value of the first dynamic reference cell.