NONVOLATILE SEMICONDUCTOR MEMORY DEVICE

摘要

PROBLEM TO BE SOLVED: To improve the error correction capability of a nonvolatile semiconductor memory device.

SOLUTION: The nonvolatile semiconductor memory device is provided with a memory cell array in which a plurality of memory cells which can store information by a difference of threshold voltages are arranged, a likelihood calculating means having a plurality of likelihood calculation algorithms for obtaining likelihood values of stored data bits by the value of threshold voltage read from the memory cell, an error correcting means performing error correction by repetition processing using the likelihood value obtained by the likelihood calculating means, and a likelihood calculation control means for changing likelihood calculation algorithms in the likelihood calculating means with the prescribed value of the number of times of repetition by repetition processing obtained by the error correcting means as a reference.

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