OPERATING MEHTOD OF MEMORY CONTROLLER AND NONVOLATILE MEMORY DEVICE

摘要

According to an embodiment of the present invention, a method for operating a memory controller for controlling a nonvolatile memory device including a plurality of memory cells is disclosed. The method comprises the following steps of: performing a default read operation based on a default voltage set to generate default raw data; performing a low-level read operation several times based on each of a plurality of read voltage sets different from the default voltage set to generate a plurality of raw data, respectively, when an error of the default raw data is not corrected; selecting a start voltage set based on the plurality of raw data when errors of the default raw data and the plurality of raw data are not corrected; and performing a high-level read operation based on the selected start voltage set to generate high-level raw data. Therefore, the present invention increases a performance and reliability in a read operation for correcting an error of data.