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:
Mar. 06, 2012
Filed:
Nov. 03, 2010
Yasuhiko Honda, Hiratsuka, JP;
Takahiro Suzuki, Chigasaki, JP;
Masao Iwamoto, Yokohama, JP;
Kiyochika Kinjo, Yokohama, JP;
Yasuhiko Honda, Hiratsuka, JP;
Takahiro Suzuki, Chigasaki, JP;
Masao Iwamoto, Yokohama, JP;
Kiyochika Kinjo, Yokohama, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
A nonvolatile semiconductor storage device capable of storing a plurality of bits of data in one memory cell by assigning multivalued data having a higher-order bit selected from one of a pair of data in a first unit and a lower-order bit selected from the other of the pair of data to each threshold voltage of the memory cell, wherein in a first write operation that processes data in the first unit, the logic of one of the higher-order bit and the lower-order bit is fixed, and two pieces of multivalued data that maximize the difference between the threshold voltages are assigned, thereby storing one bit of input data in the one memory cell in a pseudo binary state, and in a second write operation that processes data in a second unit larger than the first unit, a plurality of bits of input data is stored in the one memory cell in a multivalued state, and parity data for error correction in the second unit is stored in the memory cell.