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. 04, 2011
Filed:
Aug. 15, 2007
Tatsuyuki Ishikawa, Yokohama, JP;
Mitsuaki Honma, Yokohama, JP;
Hironori Uchikawa, Yokohama, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
This memory device comprises a word-line control circuit applying a read voltage and a soft-value read voltage as a word line voltage to a word line to generate soft-values. The soft-value read voltage is between an upper limit and a lower limit of each of plural threshold voltage distributions. A likelihood calculation circuit calculates a likelihood value of data stored in a memory cell based on the soft-value. An error correction circuit executes data error correction for the data read from the memory cell based on the likelihood value. A refresh control circuit controls a timing of a refresh operation for the memory cell based on the soft-value or the likelihood value.