| 摘要 |
PURPOSE: A semiconductor memory device for storing multi-bit data is provided to prevent over precharging bit lines at the initial operation of the bit line precharge operation to stabilize the read operation. CONSTITUTION: The semiconductor memory device for storing multi-bit data includes at least one memory cells, bit lines, a bias voltage generating circuit, a current providing circuit, a deliver circuit, and an over precharge preventing circuit. The bias voltage generating circuit generates a bias voltage of the first level during a standby period and the bias voltage of the second level lower than the first level during a plurality of sensing periods to detect the status of the memory cells. The current providing circuit provides current to the bit lines during the sensing periods for detecting the status of the memory cells with response to the first signal. The deliver circuit provides the current from the current providing circuit to the bit line with response to the bias voltage. The sensing period is divided into a bit line precharge, a sensing and a discharge period. The over precharge preventing circuit provides the bias voltage to the deliver circuit with response to the second signal representing the bit line discharge period and prevents the bit line from being over precharged.
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