Patent ID: 7450357

Claim:
An electrostatic discharge (ESD) protection circuit for bypassing an ESD current between a first pad and a second pad, the ESD protection circuit comprising: a detection circuit for detecting the ESD current, the detection circuit is coupled between the first pad and the second pad, comprising: a second resistor, coupled between the first pad and a second node; a capacitor, coupled between the second pad and the second node; a first inverter, wherein an input terminal of the first inverter is coupled to the second node, and an output terminal of the first inverter is coupled to an output terminal of the detection circuit; and a second inverter, wherein an input terminal of the second inverter is coupled to the second node, and an output terminal of the second inverter is coupled to a control gate of a gate coupled diode; and a bypass circuit, comprising: a first transistor for bypassing the ESD current; the gate-coupled diode, having the control gate; and a first resistor, wherein a drain of the first transistor is coupled to the first pad, a source of the first transistor is coupled to the second pad and a cathode of the gate-coupled diode, a substrate terminal of the first transistor is coupled to an anode of the gate-coupled diode and an output terminal of the detection circuit, the first resistor is coupled between the substrate terminal and the second pad to perform a parallel connection with the gate-coupled diode, and when receiving an ESD voltage applied to the ESD protection circuit, the gate-coupled diode keeps a voltage of the substrate terminal sufficient for turning on the first transistor, wherein the control gate of the gate-coupled diode regulates a bypassing capacity of the ESD current of the gate-coupled diode.