Patent ID: 8194373

Claim:
An integrated circuit having a plurality of circuit blocks, each block having one or more positive voltage supply pads, one or more negative voltage supply pads, and one or more signal pads, the integrated circuit further comprising an electrostatic protection circuit comprising: a first electrostatic discharge protection rail for connection to a positive voltage supply point; a second electrostatic discharge protection rail connected directly to said negative voltage supply pads, the second electrostatic discharge protection rail being further configured for connection to a negative voltage supply point; a first protection circuitry coupling each said signal pad to both said first and second electrostatic discharge protection rails, the first protection circuitry being configured to provide a conduction path to one of the first and second electrostatic discharge protection rails in the event of an excessive voltage being present on one of said signal pads; and a second protection circuitry coupling each said positive voltage supply pad to said first electrostatic discharge protection rail, the second protection circuitry being configured to provide a conduction path to the first electrostatic discharge protection rail in the event of an excessive voltage being present on one of said positive voltage supply pads.