Patent ID: 7291888

Claim:
An electrostatic discharge (ESD) protection circuit for dissipating an ESD current from a first pad to a second pad during an ESD event, the circuit comprising: a first bipolar transistor having an emitter coupled to the first pad; a second bipolar transistor having a base and a collector coupled to the second pad; and one or more bipolar transistors sequentially coupled between the first and second bipolar transistors in a base-to-emitter manner, wherein each collector of the first bipolar transistor and the sequentially coupled transistors is connected to a base of a subsequently coupled bipolar transistor for helping to turn on the first, second and sequentially coupled bipolar transistors to provide a current path from the first pad to the second pad during an ESD event, wherein a number of bipolar transistors separating the first bipolar transistor and the subsequently coupled bipolar transistor varies to adjust a trigger-on voltage of the ESD protection circuit.