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:
Mar. 04, 2003
Filed:
Aug. 24, 2001
Applicant:
Inventors:
Takayuki Yoneda, Kawasaki, JP;
Yasuhiko Tanuma, 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
A nonvolatile semiconductor memory device includes a memory cell array, a control circuit which repeatedly perform an automatic erasure operation with respect to an entirety of the memory cell array, the automatic erasure operation including a preparatory write operation prior to an erasure operation and a following erasure operation, and a counter which counts how many times the automatic erasure operation is performed with respect to the entirety of the memory cell array, wherein the control circuit stops the automatic erasure operation in response to an event that the counter counts a desired number.