Memory controller, memory system including the same, and operation method of memory controller for performing read operation based on read voltage level

Abstract

Provided is a method of operating a memory controller for controlling a memory device including a plurality of memory cells, the method including transmitting a valley search command for threshold voltage distribution of the memory cells to the memory device, obtaining a cell count value and a valley voltage level from the memory device, obtaining a determined offset value by searching an offset table based on the cell count value and the valley voltage level, and determining a corrected read voltage level by correcting the valley voltage level based on obtained the offset value, wherein the memory device is controlled so that the memory device performs a read operation through the corrected read voltage level.