US Patent 7113377 Electrostatic discharge protection device comprising several thyristors

An electrostatic discharge protection device comprises several thyristors which are connected in parallel between two nodes of an electrical circuit. It also includes a control circuit having an output connected to the control trigger terminal input of each of the thyristors. In response to an abnormal variation in a voltage between the two nodes being detected, the control circuit initiates a triggering current on the output so as to trigger the thyristors to conduct current between the two nodes. Preferably, the thyristors are arranged in a semiconductor substrate so as to have low hold voltages and small geometrical dimensions.