Patent ID: 8724269

Claim:
An ESD protection circuit comprising: a first supply terminal, a second supply terminal and a third supply terminal for coupling a first supply voltage, a second supply voltage and a base supply voltage respectively; a detection circuit having a first respond terminal and a second respond terminal, and comprising: a first capacitor coupled between the first respond terminal and the second respond terminal; a second capacitor coupled between the second respond terminal and the third supply terminal; a first resistance circuit coupled between the first supply terminal and the first respond terminal for providing a first equivalent resistance between the first supply terminal and the first respond terminal; and a resistor coupled between the second supply terminal and the second respond terminal; a trigger circuit having a first trigger terminal and a second trigger terminal, and comprising: a first trigger transistor coupled between the first respond terminal, the first supply terminal and the first trigger terminal; a second trigger transistor coupled between the second respond terminal, the first trigger terminal and the second trigger terminal; and a third trigger transistor coupled between the second respond terminal, the second trigger terminal and the third supply terminal; and a clamp circuit having a first controlled terminal and a second controlled terminal respectively coupled to the first trigger terminal and the second trigger terminal, and comprising: a first clamp transistor having a first gate, a first drain and a first source respectively coupled to the first controlled terminal, the first supply terminal and a first node; a second clamp transistor having a second gate, a second drain and a second source respectively coupled to the second controlled terminal, the first node and the third supply terminal; and a second resistor having a first connection terminal and a second connection terminal, wherein the first connection terminal is coupled to the second supply terminal, and the second connection terminal is directly connected to the first controlled terminal and the first trigger terminal.