Semiconductor memory device

摘要

A semiconductor memory device including a memory cell array having a plurality of memory cells requiring refresh, a first internal address generation circuit, a timer circuit that operates in response to a control signal input externally and generates a periodic pulse signal, and a second internal address generation circuit that operates in response to an output signal from the timer circuit. The first internal address generation circuit generates a refresh address of the entire memory region, and the second internal address generation circuit generates a refresh address of a certain part of the regions. By carrying out refresh of only a part of the memory required to be retained, the electric power consumption can be reduced.