Method of reading memory cells with different threshold voltages without variation of word line voltage and nonvolatile memory device using the same

摘要

A soft-decision read method of a nonvolatile memory device includes receiving a soft-decision read command, applying a read voltage to a selected word line, pre-charging bit lines respectively connected to selected memory cells of the selected word line, continuously sensing states of the selected memory cells. The pre-charged voltages of the bit lines and the read voltage supplied to the selected word line are not varied during the sensing states of the selected memory cells.

主权项

1. A read method of a nonvolatile memory device which includes memory cells, the read method comprising:
supplying a read voltage to a selected word line connected to a selected memory cell; applying a pre-charged voltage to a bit line connected to the selected memory cell; varying voltage of a sensing node corresponding to the bit line connected to the selected memory cell during a first time; latching the varied voltage of the sensing node as first data; boosting the sensing node by using a capacitor connected to the sensing node; varying voltage of the sensing node corresponding to the bit line connected to the selected memory cell during a second time different from the first time; and latching the varied voltage of the boosted sensing node as second data, wherein the read voltage applied to the selected word line and the pre-charged voltage applied to the bit line are maintained constantly during the first time and the second time.