Patent ID: 7643258

Claim:
An electrostatic discharge protection circuit, comprising: a first silicon controlled rectifier, comprising a first metal-oxide-semiconductor transistor, wherein a cathode of the first silicon controlled rectifier is coupled to a first power source, and an anode of the first silicon controlled rectifier is coupled to an electrostatic (ESD) bus; a second silicon controlled rectifier, comprising a second metal-oxide-semiconductor transistor, wherein an anode of the second silicon controlled rectifier is coupled to the first power source, a cathode of the second silicon controlled rectifier is coupled to the ESD bus, and both gates of the first and the second metal-oxide-semiconductor transistors are coupled to the first power source or ESD bus; and a parasitic diode, wherein a cathode of the parasitic diode is coupled to the first power source, and an anode of the parasitic diode is coupled to the ESD bus, wherein the first silicon controlled rectifier and the second silicon controlled rectifier are the same type, and the anodes of the first and second silicon controlled rectifiers are both disposed in the same well.