Memory Systems and Methods

Abstract

The memory system of an embodiment of the present invention includes a memory device and a memory controller. The memory device includes a plurality of memory cells. The memory controller is configured to determine a first voltage based on information relating to the gradient of the threshold voltage distribution of each of the plurality of memory cells, and perform a tracking operation. During the tracking operation, the memory controller causes the memory device to perform a plurality of read operations using a plurality of read levels, targeting the plurality of memory cells. In each of the plurality of read operations, the memory controller obtains the number of activated cells. The memory controller sets the first voltage difference between the plurality of read levels in the voltage range below the first voltage and the second voltage difference between the plurality of read levels in the voltage range above the first voltage to be different from each other.

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