Operation method of nonvolatile memory device and storage device

Abstract

An method of operating a nonvolatile memory device including a plurality of memory cells comprises receiving a read command from an external device, in response to the read command, performing, based on a reference voltage, a first cell counting operation with respect to the plurality of memory cells, adjusting at least one read voltage of first through nth read voltages (where n is a natural number greater than 1) based on a first result of the first cell counting operation, and performing, based on the adjusted at least one read voltage, a read operation corresponding to the read command with respect to the plurality of memory cells.

What is claimed is: 
     
         1 . A storage device comprising:
 a nonvolatile memory device including a plurality of memory blocks, each of the plurality of memory blocks including a plurality of memory cells stacked in a direction perpendicular to a substrate; and   a memory controller configured to transmit a first read command to the nonvolatile memory device;   wherein, in response to the first read command, the nonvolatile memory device is configured to:   perform, using a reference voltage, a first sensing operation on a first memory cells connected with a first wordline, among of the plurality of memory cells;   adjust at least one read voltage of a plurality of read voltages based on a result of the first sensing operation; and   perform, using the adjusted at least one read voltage, at least one second sensing operation on the first memory cells to read first page data stored in the first memory cells.