Patents Represented by Attorney Eugene Worley
  • Patent number: 7724485
    Abstract: An electrostatic discharge (ESD) protection circuit uses two N-channel field effect transistors (NFETs) to conduct ESD current from a first to a second supply node. During the ESD event, an ESD detection circuit couples the gates of both NFETs to the first supply node through separate conductive paths. In one novel aspect, an RC trigger circuit includes a capacitance that is charged through a resistance. The resistance involves a P-channel transistor whose gate is coupled to the gate of the second NFET. During a normal power-up condition, the P-channel transistor is conductive, thereby preventing the RC trigger from triggering if the supply voltage VDD were to rise rapidly. In another novel aspect, a novel level-shifting inverter drives the second NFET. The level-shifting inverter uses a pull down resistor to avoid snap-back and also isolates the gate of the second NFET from a capacitively loaded third supply node.
    Type: Grant
    Filed: April 20, 2007
    Date of Patent: May 25, 2010
    Assignee: QUALCOMM Incorporated
    Inventors: Eugene Worley, Vivek Mohan, Reza Jalilizeinali