Patent ID: 8115270

Claim:
An electrostatic discharge protection device that protects a semiconductor device from a surge current impressed between a first power supply terminal or a second power supply terminal and an input/output terminal, comprising: a first bipolar transistor having a collector terminal connected with the first power supply terminal, an emitter terminal connected with the input/output terminal, and a base terminal connected with the second power supply terminal; and a second bipolar transistor having a collector terminal connected with the second power supply terminal, an emitter terminal connected with the input/output terminal, and a base terminal connected with the first power supply terminal, one of the first and second bipolar transistors ensuring a continuity between the collector terminal and emitter terminal under such conditions that a potential difference between the first or second power supply terminal and the input/output terminal is lower than a breakdown voltage at a PN junction between the emitter terminal and the base terminal of the other bipolar transistor.