Refresh control circuit and semiconductor memory device and memory system including the same

摘要

A semiconductor memory device includes a refresh control circuit and a memory cell array. The refresh control circuit generates an internal auto refresh control signal based on a chip select signal and an external self refresh control signal. The memory cell array is refreshed in response to the internal auto refresh control signal. Because the semiconductor memory device internally generates the internal auto refresh control signal performing auto refresh operations, the semiconductor memory device may not be required to transmit to external devices for performing the auto refresh operations, and thus pins or pads for transmitting signals may be reduced and operation time may become faster.