ELECTROSTATIC PROTECTION CIRCUIT

摘要

<P>PROBLEM TO BE SOLVED: To provide an electrostatic protection circuit capable of reducing the size of a circuit area, and protecting the gate oxide films of MOS transistors from electrostatic surge. Ž<P>SOLUTION: The electrostatic protection circuit is used for a semiconductor device which includes a plurality of power source systems separated in power source and to be driven by the same voltage in a normal operation and where a signal is exchanged between the first and second circuits to be operated by the different power source systems. The electrostatic protection circuit includes protecting circuits inserted onto signal lines. The protecting circuits are two serially connected native MOS transistors with negative thresholds. The gates of the two native MOS transistors are respectively connected to the high-potential power sources of the first and second circuits. The gate oxide films are formed to be thicker than the gate films of the MOS transistors constituting the first and second circuits. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž