| 摘要 |
PROBLEM TO BE SOLVED: To provide an input circuit that can be operated by a 3.3 V system power supply voltage and can interface a CMOS circuit. SOLUTION: When giving low level to an input terminal IN of this input circuit, an input voltage to an input buffer B2 consisting of transistors(TRs) 8, 9 becomes 0 V, and a voltage of 3.3 V is outputted to an output terminal OUT. When a high level is given to the input terminal IN, the input voltage to the input buffer B2 is divided by resistors 6, 7 and reaches about 4.6 V, a PMO TR 8 is turned off, an NMOS TR 9 is turned on, a 0 V is outputted to the output terminal OUT, and a gate voltage applied to the TRs 8, 9 changes from 0 V not in excess of their breakdown voltage input 4.6 V and, even if the TRs 8, 9 are switched at a voltage around 2.5 V through a CMOS interface, stable characteristics can be obtained.
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