Patent ID: 8514532

Claim:
A circuit for providing electrostatic discharge protection, the circuit comprising: a first power supply rail to receive a first voltage; a second power supply rail to receive a second voltage; a first series resistor-capacitor circuit coupled to the first power supply rail and the second power supply rail and configured to detect an electrostatic discharge event without detecting a fast ramping power supply as an electrostatic discharge event; a first transistor comprising a first terminal, a second terminal, and a gate, the first terminal of the first transistor coupled to the first power supply rail, the second terminal of the first transistor coupled to the second power supply rail, and the gate of the first transistor coupled to the first series resistor-capacitor circuit, wherein upon the detection of the electrostatic discharge event the first series resistor-capacitor circuit causes the first transistor to enter an active mode and shunt a first current from the first power supply rail to the second power supply rail; a third transistor comprising a first terminal, a second terminal, and a gate, the first terminal of the third transistor coupled to the first power supply rail, the second terminal of the third transistor coupled to the first series resistor-capacitor circuit, and the gate of the third transistor coupled to the gate of the first transistor, wherein the third transistor is configured to maintain the first transistor in the active mode by passing a third current to the first series resistor-capacitor circuit that prevents the first series resistor-capacitor circuit from discharging; and a second series resistor-capacitor circuit coupled to the first power supply rail and the second power supply rail and configured to cause the first transistor to enter a cutoff mode at the end of a discharge period following the electrostatic discharge event.