Patent ID: 7106568

Claim:
An electrostatic discharge (ESD) protection circuit formed on a P-type substrate comprising: a first power terminal; a second power terminal; a resistor connected to the first power terminal; a capacitor connected between the resistor and the second power terminal; a first p + diffusion region in the P-type substrate connected to the second power terminal; an N-well in the P-type substrate; a first n + diffusion region in the N-well connected to the first power terminal; a P-well in the N-well; at least a second p + diffusion region in the P-well, at least a second n + diffusion region in the P-well connected to the first power terminal, and at least third n + diffusion region in the P-well connected to the second power terminal; and an ESD detecting circuit connected to the first power terminal having an input terminal connected to the resistor and the capacitor and a output terminal connected to the second p + diffusion region, wherein the output terminal outputs signal opposite to signal received by the input terminal so as to change a voltage level of the P-well.