Patent ID: 8922962

Claim:
An integrated circuit comprising: a supply node; a ground node; and a power clamp circuit coupled between the supply node and the ground node to protect the integrated circuit from a surge in voltage on the supply node, the power clamp circuit including; a breakdown circuit coupled to the supply node to enter breakdown and conduct current away from the supply node when a voltage on the supply node exceeds a breakdown voltage; at least one transistor coupled between the supply node and an intermediate node, the at least one transistor to turn on if the current through the breakdown circuit exceeds a predetermined level to provide a current flow path from the supply node to the intermediate node; a voltage regulation circuit coupled to the supply node; and a current controlled switch coupled to the voltage regulation circuit, the ground node, and the intermediate node, the current controlled switch to connect the voltage regulation circuit to the ground node if a current flowing between the intermediate node and the ground node exceeds a threshold level, wherein the voltage regulation circuit is configured to, when connected to the ground node, cause the voltage on the supply node to snap back to a value that is lower than a breakdown voltage associated with the at least one transistor to improve the robustness of the power clamp circuit to electrostatic discharge (ESD).