Patent ID: 8760919

Claim:
A method of reading data in a nonvolatile memory device, the method comprising: performing a first read operation on a plurality of multi-level memory cells (MLCs); performing a first sensing operation on at least one flag cell corresponding to the plurality of MLCs; selectively performing a second read operation on the plurality of MLCs based on a result of the first sensing operation; performing a second sensing operation on the at least one flag cell when the second read operation is performed; and outputting read data based on a result of the first read operation and the result of the first sensing operation when the second read operation is not performed, and outputting the read data based on the result of the first read operation, the result of the first sensing operation, a result of the second read operation and a result of the second sensing operation when the second read operation is performed, the read data corresponding to programmed data in the plurality of MLCs.