ESD PROTECTION CIRCUIT OF SEMICONDUCTOR CONTROLLED RECTIFIER STRUCTURE CAPABLE OF OPERATING AT LOW TRIGGER VOLTAGE

摘要

An ESD protection circuit having silicon-controlled rectifier structure, includes a PNP transistor and an NPN transistor. A switch circuit is connected between a ground voltage terminal and a well region that is a base of the PNP transistor. The switch circuit is formed of plural diode-coupled MOS transistors, so that a trigger voltage of the SCR is determined by threshold voltages of the MOS transistors.