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. 08, 2015
Filed:
Apr. 28, 2011
Akifumi Suzuki, Nakai, JP;
Takashi Tsunehiro, Ebina, JP;
Akifumi Suzuki, Nakai, JP;
Takashi Tsunehiro, Ebina, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A semiconductor storage apparatus comprises a memory controller and flash memories which include a plurality of blocks as storage areas. The memory controller is configured to manage a degree of deterioration and read frequency for each of the plurality of blocks. A reliability maintained period is calculated for each storage area based on the degree of deterioration and read frequency for each storage area of a flash memory, and refresh is executed on each storage area in a planned manner based on the calculated reliability maintained period by newly storing the data stored in a block in another block based on an obtained reliability maintained period. The memory controller may also be configured to execute verification on each block and, if the number of failure bits is larger than a predetermined threshold, execute refresh to store data which is stored in a verification target block in another block.