Patent ID: 8599529
Filing Date: 2013-12-03
Classification: H02G,H02H

Abstract:
1. A device for protecting electric circuitry against high input voltages, said device including a Gas Discharge Tube (GDT) for discharging high currents, said GDT being connected between an input of said device and ground, and being provided with a trigger electrode connected to a secondary side of a transformer, said transformer being arranged for producing a trigger signal in response to a voltage on said input for triggering said GDT into a conducting state wherein, a primary side of said transformer is connected to said input via a capacitor and a resistance, wherein a current flowing from said input through said resistance charges said capacitor, when said voltage on said input increases, and further comprising: a thyristor connected to ground, from a point between said resistance and said capacitor, said thyristor being arranged to start conducting when said input voltage reaches a predetermined level exceeding the normal operating voltage level, thereby discharging said capacitor through said thyristor to ground and creating a pulse on said primary side of said transformer, said pulse being transformed into said trigger signal by said transformer.