Patent ID: 7446991

Claim:
A protection circuit for bypassing a current induced by an ESD event, the protection circuit comprising: a trigger circuit coupled between a first pad and a second pad for comparing a voltage of the first pad and a voltage of the second pad; wherein the trigger circuit generates a triggering signal when the voltage difference between the first pad and the second pad is exceeds to a first predetermined value; and an ESD clamp circuit coupled to the first pad and the third pad equipped with a controlled node, the ESD clamp circuit serves as a conductive path between the first pad and the third pad when the controlled node of ESD clamp circuit receives the triggering signal; wherein the second pad is coupled to an decoupling capacitor, and the voltage of the second pad is lower than the voltage of the first pad by less than the first predetermined value when the ESD event happens between the first pad and the third pad.