INTEGRIERTE HALBLEITERSCHALTUNGSEINRICHTUNG

摘要

An interconnection circuit of a semiconductor integrated circuit connected between a first circuit (41) for applying an input signal and the second circuit (44) for outputting an output signal to the other circuit comprises circuits of input stage, processing stage and output stage. The circuit of the input stage comprises an n channel MOS field effect transistor (14) and a resistance (7). The circuit of the processing stage comprises two CMOS inverters (1, 2, 31, 32). The circuit of the output stage comprises a CMOS inverter (15, 16) and a series connection of a resistance (21), an npn bipolar transistor (17) and an n channel MOS filed effect transistor (18). When an overvoltage is applied to the input terminal (8), the circuit of the input stage protects the circuit by a parasitic diode (25) formed by the transistor (14) or the punch through phenomenon of the transistor (14). When the power supply Vcc of the interconnection circuit is off, when the output of the first circuit (41) or the output of the second circuit (44) is brought to a high level voltage, no current flows into the interconnection circuit. Therefore, malfunctions of the first and second circuits can be prevented.