| 摘要 |
PURPOSE:To obtain a semiconductor integrated circuit device with a protective circuit having high reliability on electrostatic breakdown by providing a MOSFET, which is brought to an OFF state by the supply of supply voltage and brought to a floating state by the interruption of supply voltage. CONSTITUTION:A MOSFETQ1 and a MOSFETQ2 constitute an inverter circuit, and an output from the circuit is coupled with a gate for a MOSFETQ3 formed between an electrode P and the grounding potential point of the circuit. The gate for the MOSFETQ3 is brought to a floating state under the state in which a semiconductor integrated circuit device having such constitution is not supplied with supply voltage Vcc. Consequently, when static electricity Q is generated in the electrode P, high voltage is generated in the electrode P. The generated voltage V is transmitted over the gate under the floating state through a capacitor Cdg, and the MOSFETQ3 is brought to an ON state, thus instantaneously discharging said charges Q, then preventing the electrostatic breakdown of an input MOSFETQ4. |
