Nonvolatile memory storage system

    公开(公告)号:US10229749B2

    公开(公告)日:2019-03-12

    申请号:US15475670

    申请日:2017-03-31

    摘要: A nonvolatile memory storage system includes a plurality of memory cells and a memory controller configured to transmit a read command to a nonvolatile memory device based on a plurality of read voltages. The nonvolatile memory device performs a first read operation on a first level among the N levels based on a first read voltage among the plurality of read voltages, counts the number of on-cells that respond to the first read voltage among the plurality of memory cells, and adjusts a level of a second read voltage to be used to perform a second read operation on the first level or a second level among the N levels among the plurality of read voltages according to a comparison result of the counted number of on-cells and the number of reference cells.