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:
Sep. 01, 2009
Filed:
Jan. 04, 2008
Osamu Iioka, Kawasaki, JP;
Naoto Emi, Kawasaki, JP;
Osamu Iioka, Kawasaki, JP;
Naoto Emi, Kawasaki, JP;
Fujitsu Microelectronics Ltd., Tokyo, JP;
Abstract
A charge loss restoration method detects a memory cell having a tendency of a charge loss within a memory cell array of an electrically writable and erasable nonvolatile semiconductor memory device, using a charge loss detecting reference cell having a threshold value set between a threshold value of a read reference cell and a threshold value of a write verify reference cell, where the threshold value of the write verify reference cell is higher than the threshold value of the read reference cell, and restores the memory cell having the tendency of the charge loss by making an additional write thereto.