Patent ID: 8279566

Claim:
An electronic device embodying an electrostatic discharge (ESD) clamp coupled across first and second terminals of a protected semiconductor device or integrated circuit included in the electronic device, comprising: a first ESD transistor with source, drain, gate and body, wherein the source of the first ESD transistor is coupled to the second terminal and the drain of the first ESD transistor is coupled to the first terminal; a first resistor coupled between the gate and the source of the first ESD transistor; a second resistor coupled between the body and the source of the first ESD transistor; and first and second control transistors having sources, drains and gates, wherein the source and drain of the first control transistor are coupled in parallel with the first resistor and the gate of the first control transistor is adapted to be coupled to a first bias voltage, and the source and drain of the second control transistor are coupled in parallel with the second resistor and the gate of the second control transistor is adapted to be coupled to a second bias voltage such that the first and second bias voltages can be adjusted to change the impedance between the second terminal and the gate of the first ESD transistor and the impedance between the second terminal and the body of the first ESD transistor to actively control the activation voltage of the first ESD transistor during operation of the electronic device.