Patent ID: 6765840
Filing Date: 2004-07-20
Classification: G11C

Abstract:
A nonvolatile memory system comprising:a controller; and a nonvolatile memory, wherein said controller is capable of controlling performing operations of said nonvolatile memory, one of which operations being a read operation to read data stored in said nonvolatile memory, wherein said nonvolatile memory comprises a plurality of nonvolatile memory cells, a plurality of sense circuits and a decision circuit, wherein each of said nonvolatile memory cells has a threshold voltage within one of a plurality of threshold voltage distributions, wherein each of said sense circuits connects to a corresponding one of said nonvolatile memory cells and is capable of outputting a signal which has one of a first level or a second level according to data stored in said corresponding nonvolatile memory cell, and wherein, in performing said read operation, said decision circuit outputs one of a first signal or a second signal, said first signal indicating that all of said sense circuits output said first level signal and said second signal indicating that at least one of said sense circuits outputs said second level signal.