LOGIC SEMICONDUCTOR INTEGRATED CIRCUIT

摘要

PROBLEM TO BE SOLVED: To surely avoid the malfunction, etc., of a logic semiconductor integrated circuit caused by a floating state without increasing the power consumption of the circuit nor requiring any special processing to an unused input terminal on the outside of the circuit. SOLUTION: A nonspecific logical level detecting circuit 2 is constituted so that the circuit 2 can output a signal having a logical value of '1' when the potential at an input terminal 1 exceeds a specific logical level range. When the signal having a logical value '1' is impressed upon the control terminal 4a of a change-over switch 4 through an OR circuit 3, the switch 4 is set to an opened state and the potential at the input terminal 1 is maintained at a specific logical level through a resistor 5.