| 摘要 |
PROBLEM TO BE SOLVED: To reduce the buildup of a signal by saving unnecessary current consumption to an irreducible minimum and switching the value of a pull up resistor, etc. SOLUTION: This input circuit and/or an output circuit consists of an output buffer 11 of an IC circuit A1 being an output stage, the input buffer 12 of and IC circuit B1 being an input stage, pull up resistors R1, R2 incorporated in the circuit B1 and inverters 21, 22 for turning on/off them. When the output of the buffer 11 of the circuit A1 is at a low level, the value of the resistors R1 to be in an on sate is increased to save unnecessary current consumption to an irreducible minimum. When the output of the buffer 11 of the circuit A1 changes to high impedance, and after the input buffer 12 of the circuit B1 reaches a level judged to be high, the value of the resistor R2 to be in an on-state is reduced, to facilitate varying of the signal from a low level to the high level.
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