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:
May. 24, 2011
Filed:
Aug. 04, 2009
Yukio Komatsu, Yokohama, JP;
Yukio Komatsu, Yokohama, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
A semiconductor memory device includes a control circuit. The control circuit executes control to perform a verify operation with respect to only a lowest threshold voltage level of a memory cell at a time of a data write operation, and to skip the verify operation with respect to the other threshold voltage levels. The control circuit determines whether a verify pass bit number of the lowest threshold voltage level, which is counted by a bit scan circuit, is a prescribed bit number or more, and the control circuit further executes control, if the verify pass bit number is the prescribed bit number or more, to perform the verify operation with respect to only the lowest threshold voltage level and a threshold voltage level that is higher than the lowest threshold voltage level, and to skip the verify operation with respect to the other threshold voltage levels.