| 摘要 |
PURPOSE: An input/output buffer using a schmitt trigger is provided to perform an optimum operation according to applicable areas by designing the input/output buffer including plural schmitt triggers having different trigger voltages. CONSTITUTION: An input/output buffer using a schmitt trigger includes a plurality of schmitt triggers(40a-40c) and a multiplexing portion. The schmitt triggers(40a-40c) have different trigger voltages in response to the same input signal. The multiplexing portion outputs selectively one of the input signal and the output signals of the schmitt triggers(40a-40c) according to a predetermined control signal. The multiplexing portion includes a multiplexer(41a) and a register(41b). The multiplexer(41a) is used for outputting selectively one of the input signal and the output signals of the schmitt triggers(40a-40c) according to a selection control signal. The register(41b) is used for outputting the selection control signal to the multiplexer(41a).
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