| 摘要 |
PURPOSE:To prevent back flow of current from the capacitor of an active pull-up circuit to a bit line even when the precharge level of the bit line is set lower than power source voltage by controlling gate potential of a transistor of the active pull-up circuit. CONSTITUTION:A transistor Q9 inserted between precharge power source voltage VPR is made on by clock phiRES', and a transistor Q7 inserted between power source voltage VCC is made on by rising of clock phiR thereafter and voltage of clock changes to VPR, VCC. The clock phiP is applied to the base,and one transistor of a pull-up circuit is controlled and this transistor is not made on from starting of sense up to completion of operation of an active pull-up circuit. Accordingly, even when the precharge level of a bit line is set lower than power source voltage, back flow of current from the capacitor of the active pull-up circuit to the bit line is prevented, and the active pull-up circuit operates effectively.
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