Diode based ESD triggers

A circuit comprising:

• a protected circuit coupled to an input voltage;
• an electrostatic discharge (ESD) detector coupled to the input voltage, the detector comprising a voltage modulated input capacitance Cj configured to decrease as the input voltage increases, wherein Cj is provided by at least one electrical component with a nonlinear voltage/impedance characteristic;
• an output pulse generator configured to amplify an output of the detector into an output pulse;
• an ESD protection switch coupled to turn on upon application of the output pulse from the output pulse generator;
• and
• a capacitance Cp different from Cj, the circuit configured such that its sensitivity to detecting ESD events and rejecting noise is set based on selection of (a) a conductive area size of the nonlinear electrical component, and (b) Cp.

A method of protecting a circuit from ESD events, comprising:

• applying an input voltage to an ESD detector that has a capacitance Cj that decreases as the input voltage increases;
• generating a signal to shunt a power supply of a protected circuit to a ground bus if a slew rate of the input voltage exceeds a preset threshold value;
• and
• setting a sensitivity and noise rejection of the detector by selecting a value for Cj and a value for a second capacitance Cp of the detector.

An apparatus comprising:

• a protected circuit;
• an electrostatic discharge (ESD) detector that has a capacitance Cj that decreases as the input voltage increases, wherein the ESD detector includes a capacitance Cp different from Cj;
• and
• a power supply coupled to apply an input voltage to the protected circuit and to the ESD detector;
• wherein the ESD detector is configured to generate a signal to shunt the input voltage of the protected circuit to a ground bus if a slew rate of the input voltage exceeds a preset threshold value;
• and
• wherein a sensitivity and noise rejection of the ESD detector are set based on selection of a value for Cj and a value for Cp.