US Patent 8174921 Semiconductor memory device having shared temperature control circuit

A semiconductor memory device includes a plurality of memory banks; a plurality of temperature sensing circuits, and a shared control circuit. The temperature sensing circuits correspond to the memory banks and each is disposed in the vicinity of a corresponding memory bank. The shared control circuit is connected to the plurality of temperature sensing circuits and a plurality of refresh circuits for refreshing the plurality of memory banks, performs calibration on the plurality of temperature sensing circuits, performs digital processing on signals for separately controlling refresh intervals for the plurality of memory banks, and transmits the processed signals to the plurality of refresh circuits. Therefore, the refresh intervals for individual channels or banks are separately or selectively controlled. Further, since the plurality of temperature sensing circuits are connected to the shared temperature control circuit, the occupied area of the circuits in a chip is reduced or minimized.