A METHOD OF OPERATING THE MEMORY DEVICE

摘要

Provided is a memory system. The memory system includes a non-volatile memory device including a plurality of memory cells where data are programmed, and a controller to control the non-volatile memory device. The controller includes a microprocessor that changes a first read voltage, which is for determining whether the data stored in the memory cell is in a first voltage state or a second voltage state, into a first select read voltage, which is one of n candidate voltages (n is natural number) having intensity varied by an amount of first voltage, and changes a second read voltage, which is for determining whether the data stored in the memory cell is in a third voltage state or a fourth voltage state, into a second select read voltage, which is one of m candidate voltages (m is natural number) having intensity varied by an amount of second voltage different from that of the first voltage; an error correction code (ECC) encoder to generate data having a parity bit by performing the error correction encoding with respect to the data provided to the non-volatile memory device; and an ECC decoder to correct the error bit of the data having the parity bit. The non-volatile memory device includes a voltage generation circuit to generate the first and second read voltages, the n candidate voltages and the m candidate voltages; an X-decoder to drive the memory cells by receiving the first and second read voltages and the first and second select read voltages generated from the voltage generation circuit; and a register to store the first and second select read voltages.