| 摘要 |
PURPOSE: An auto refresh control circuit and a semiconductor memory device thereof are provided to execute a simultaneous auto refresh operation and an individual auto refresh operation by controlling control signals in two rank DRAM system. CONSTITUTION: A control signal generating unit(100) simultaneously enables a first and a second control signal in response to an information combination signal with refresh information and an operation mode information, a first and a second chip select signal. The control signal generating unit individually enables the first and the second control signal in response to the information combination signal, the first and the second chip select signal. An auto refresh signal generating unit(200) generates a first and a second auto refresh signal in response to a plurality of command signals, the first and the second control signal. A signal combination unit(110) generates the information combination signal according to the refresh information signal and an operation mode signal.
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