| 摘要 |
PURPOSE:To carry out a refresh operation correctly by providing a set up circuit in a shift register for refresh and making only 1 bit of the content of the shift register a selection level. CONSTITUTION:For instance, when the output of an SRO is 1 (selection level), a set up circuit 6 treats a specific step as a reset signal RST and resets all the remaining steps SR1-SR511 and makes outputs thereof 0 (non-selection level). This circuit 6 makes the output of the specific step SRO1 when all the steps of a shift register 2 are 0 outputs. In this manner, by a refresh operation thereafter, the destruction of a cell information resulting from the multiple selection of a word line can be avoided and the matter that all the maintaining data of the shift register is 0, the word line is not selected and the refresh is not performed can be avoided.
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