Patent ID: 8243403

Claim:
An electrostatic discharge (ESD) clamp circuit, comprising: a first resistor, having a first end coupled to a first rail; a second resistor, having a second end coupled to a second rail; a first transistor, wherein a control end of the first transistor is coupled to a first end of the second resistor, and a second end of the first transistor is coupled to the second rail; a first diode unit, having two ends coupled to a second end of the first resistor and a first end of the first transistor respectively; a second transistor, wherein a control end of the second transistor is coupled to the second end of the first resistor, a first end of the second transistor is coupled to the first rail, and a second end of the second transistor is coupled to the first end of the second resistor; and a third transistor, wherein a control end of the third transistor is coupled to the first end of the second resistor, a first end of the third transistor is coupled to the first rail, and a second end of the third transistor is coupled to the second rail.