| 摘要 |
Input circuit having an input terminal for accepting an input signal varying between "high" and "low" voltage magnitudes, wherein the input circuit is provided with a compensated threshold voltage located between the "high" and "low" voltage magnitudes for properly characterizing the status of the input signal depending upon whether the input signal has a voltage above or below the threshold voltage. The input circuit has a load circuit disposed between a power supply side and an input stage of the input circuit. The load circuit includes a logic element and operates to temporarily increase the threshold voltage associated with the input stage in response to noise generated at the ground side of the input circuit, thereby preventing the noise level from surpassing the threshold voltage as temporarily increased. The compensated threshold voltage enables the input circuit to avoid malfunction by putting out an output signal appearing to have an incorrect "low" status rather than the correct "high" status otherwise caused by the generation of noise at the ground side at a level greater than the normal threshold voltage of the input circuit.
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