Semiconductor memory device

Abstract

A memory may includes: word lines; bit lines; memory array blocks including memory cells, each memory array block being a unit of a data read operation or a data write operation; a row decoder configured to selectively drive the word lines; sense amplifiers configured to detect data; and an access counter provided for each memory cell block, the access counter counting the number of times of accessing the memory array blocks in order to read data or write data, and activating a refresh request signal when the number of times of access reaches a predetermined number of times, wherein during an activation period of the refresh request signal of the access counter, the row decoder periodically and sequentially activates the word lines of the memory array blocks corresponding to the access counter, and the sense amplifier performs a refresh operation of the memory cells connected to the activated word lines.