| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of a conventional input circuit that has misjudged a level change in an input signal received at an external terminal from a level change due to a noise when a threshold value of a CMOS buffer is lower than a threshold value of a Schmitt trigger buffer. SOLUTION: The input circuit is provided with a CMOS buffer 3a whose input terminal is connected to an output terminal of a Schmitt trigger buffer 2 and whose output terminal is connected to an output terminal of a CMOS buffer 3b and with a selection means that activates either of the CMOS buffers 3a, 3b and deactivates the other depending on a level at the output terminal of the Schmitt trigger buffer 2.
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