| 摘要 |
PURPOSE: An output buffer is provided to drive a pull-up transistor and a pull-down transistor of the output buffer by using voltages generated from a negative charge pump and a positive charge pump. CONSTITUTION: A positive charge pump(26) generates a positive voltage. A negative charge pump(24) generates a negative voltage. The first logic portion(21) performs a logical operation for an output enable bar signal and an output signal of a sense amplifier. The second logic portion(22) performs a logical operation for an output enable signal and an output signal of the sense amplifier. The first level shifter(23) outputs the negative voltage according to an output signal of the first logic portion. The second level shifter(25) outputs the positive voltage or a ground voltage according to an output signal of the first logic portion. The first and the second switching portions control electric potential of output terminals according to output signals of the first and the second level shifters.
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