Patent ID: 8730634

Claim:
An electrostatic discharge (ESD) protection circuit comprising: a first silicon controlled rectifier (SCR) having an anode terminal as a first coupling terminal, a second coupling terminal and a control terminal; and a trigger circuit comprising: a first metal-oxide-semiconductor (MOS) transistor having a first drain, a first bulk, a first source and a first gate; one of the first drain and the first bulk being coupled to the control terminal, and the first source being coupled to the second coupling terminal; and a second SCR formed by a portion of the first MOS transistor and one of the following circuits: a second MOS transistor having a second gate insulated from the first gate, and a second drain coupled to the first gate; a bipolar junction transistor having a second base, a second emitter directly connected to the second base, and a second collector coupled to the first gate; and a main diode having a main anode and a main cathode respectively coupled to the first gate and the first coupling terminal.