Nonvolatile memory device preventing overshoot of internal voltage and method of operating nonvolatile memory device

Abstract

In a method of operating a nonvolatile memory device that includes a memory block including cell strings where each of the cell strings includes a string selection transistor, memory cells and a ground selection transistor which are connected in series and disposed in a vertical direction, each of word-lines coupled to the memory cells is set up to a respective target level during a word-line set-up period, a sensing operation on target memory cells is performed by applying a read voltage to a selected word-line coupled to the target memory cells while applying a read pass voltage to unselected word-lines during a sensing period, and while consuming an internal voltage connected to the unselected word-lines in a particular circuit in the nonvolatile memory device, a voltage level of the unselected word-lines is recovered to a level of the internal voltage during a discharge period of a word-line recovery period.