摘要 |
In order to provide a multi-valued DRAM with an access time comparable to ordinary binary DRAMs, a potential difference generated by a memory cell between a pair of bit-lines is delivered to N-1 sets of sense amplifiers. Each delivered potential difference is shifted by a predetermined value for each sense amplifier for classifying the potential difference into N levels. A refreshing potential for the memory cell is obtained from outputs of the sense amplifiers activated with sense amplifier activating signals having potentials predetermined for each sense amplifier.
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