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. 09, 2007
Filed:
Mar. 17, 2006
Kenji Misumi, Kyoto, JP;
Makoto Kojima, Osaka, JP;
Kenji Misumi, Kyoto, JP;
Makoto Kojima, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
Even when the number of rewrite operations varies among erase unit areas, the number of rewrite operations is improved for all of the erase unit areas. A flash EEPROMcomprises a trimming value storing areaof storing a trimming value corresponding to each erase unit areaincluded in a memory cell array. When an erase operation and a write operation are performed with respect to a certain erase unit area, a regulator circuitconverts a voltage boosted by a booster circuitto a level corresponding to the trimming value for the erase unit area. When a read determination circuitdetects an abnormality as the number of rewrite operations is increased, the trimming value is updated to a value which causes the regulator circuitto increase the output voltage.