Patent ID: 7245467

Claim:
An ESD (electrostatic discharge) circuit for protecting a first internal circuit and a second internal circuit from an electrostatic charge, the first internal circuit coupled between two terminals VDD 1 and VSS 1 and the second internal circuit coupled between two terminals VDD 2 and VSS 2 , the ESD circuit comprising: a first transistor set comprising at least one transistor coupled between VDD 1 and VDD 2 ; a first detecting circuit coupled between VDD 1 and VSS 1 for detecting the electrostatic charge, and coupled to the first transistor set; a second detecting circuit coupled between VDD 2 and VSS 2 for detecting the electrostatic charge, and coupled to the first transistor set; and a second transistor set comprising at least one transistor coupled between VSS 1 and VSS 2 ; wherein if the first detecting circuit or the second detecting circuit detects the electrostatic charge injected into the VDD 1 or the VDD 2 , the first transistor set is turned on to discharge the electrostatic charge; wherein if the first detecting circuit or the second detecting circuit detects the electrostatic charge injected into the VDD 1 or the VDD 2 , the second transistor set is turned on to discharge the electrostatic charge.