Adaptable electrostatic discharge clamp trigger circuit

A method implemented in an Electrostatic Discharge (ESD) clamp control circuit that includes a pull-up device having a first terminal connected to a supply voltage and a second terminal connected to a control node of a pull-down device that controls switching of the clamp control circuit, the method comprising:

• when the supply voltage is in a non-ESD range and the pull-up device is off, sinking a first current through one or more depletion-mode Metal Oxide Semiconductor (MOS) devices connected to the control node of the pull-down device to ensure that the voltage of the control node of the pull-down device is substantially stable, each depletion-mode MOS device having a negative threshold voltage;
• and
• when the supply voltage is in an ESD range, sinking a second current through the one or more depletion-mode MOS devices such that the second current is less than a current through the pull-up device and the voltage of the control node of the pull-down device increases, the second current is the saturation current of the one or more depletion-mode MOS devices.