ESD protection circuit and circuitry of IC applying the ESD protection circuit

摘要

A circuitry of an IC is provided, including a pad, an internal circuit, and an ESD protection circuit. The pad transmits or receives a signal and is coupled to a first node. The internal circuit is coupled to the first node for processing the signal. The ESD protection circuit includes an ESD clamping circuit, a first current limiting and shunting unit and a second current limiting and shunting unit. The ESD clamping circuit is coupled to the first node, for clamping an ESD current flowing through the first node. The first current limiting and shunting unit is through the first node coupled to the pad, for limiting the ESD current and shunting part of the ESD current to a first voltage path. The second current limiting and shunting unit is coupled to the first current limiting and shunting unit, for limiting the ESD current and shunting part of the ESD current to a second voltage path.