Semiconductor memory device and refresh method for the same
AssigneeFujitsu Limited
InventorsHajime Sato, Yuji Nakagawa, Satoru Kawamoto
Life of this patent
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Abstract
A refresh method for a semiconductor memory device features high noise resistance, lower power consumption, and lower cost. All word lines of one or more memory cell blocks that have not been selected in a self refresh mode are controlled to have a floating potential substantially at ground level. Even when a word line and a bit line are short-circuited, this control prevents destruction of memory cell information, which may be caused by noise, and also prevents generation of leakage current. A fuse, etc., for preventing generation of leakage current is unnecessary, so that lower cost is realized.
Claims8
A semiconductor memory device, comprising:
- a plurality of memory cell blocks that are selectively refreshed in refresh mode, each memory cell block having a word line;
- and
- a word line control circuit for generating a control signal that controls one or more word lines, which are associated with one or more memory cells that have not been selected in the refresh mode, to have a floating potential in accordance with a refresh mode signal and a memory cell block selection signal.
A semiconductor memory device, comprising:
- a plurality of memory cell blocks that are selectively refreshed in refresh mode, each memory cell block having a word line;
- a plurality of word line drive circuits, connected to the plurality of memory cell blocks, each for driving a word line of the corresponding memory cell block;
- and a plurality of word line control circuits, connected to the plurality of word line drive circuits, for deactivating one or more word line drive circuits associated with one or more memory cell blocks that have not been selected in the refresh mode, and controlling one or more word lines, which are associated with the one or more memory cell blocks that have not been selected, to have a floating potential.
Dependencies are inferred from the claim text.