Patent ID: 7286331
Filing Date: 2007-10-23
Classification: H01L

Abstract:
1. An electrostatic protection device for protecting an internal circuit of a semiconductor device from static electricity introduced into an input/output port of the semiconductor device, the electrostatic protection device comprising: a delivery unit that induces static electricity introduced to the input/output port to a first reference potential voltage line for the semiconductor device; a detection unit detecting the static electricity induced from the input/output port to the voltage line and outputting a detected voltage obtained by a voltage drip with respect to the static electricity; and a PMOS transistor coupled in series to an NMOS transistor, wherein the PMOS has its source coupled to said output terminal, its gate coupled to the first reference potential voltage line and its drain is connected to the drain of the NMOS transistor to form commonly-connected drains, the gate of the NMOS transistor is coupled to the first reference potential line and the source of the NMOS transistor is coupled to a second reference potential line for the semiconductor device; and the commonly connected drains are coupled to and control a third MOS transistor coupled across the first and second reference potential lines and which shunts static electricity to the second reference potential line.