Patent ID: 7888986

Claim:
A circuit for controlling a thyristor (V 1 ) into conducting state, the thyristor (V 1 ) being in a rectifier, which rectifier is adapted to supply a DC voltage to a DC voltage circuit, characterized in that the circuit comprises a trigger capacitor (C 2 ) adapted to be charged from the voltage difference across the thyristor (V 1 ), when the anode-to-cathode voltage of the thyristor is positive, a zener diode (V 5 ) adapted to be triggered with the voltage of the trigger capacitor (C 2 ), when the voltage of the trigger capacitor (C 2 ) exceeds the breakdown voltage of the zener diode (V 5 ), and an auxiliary thyristor (V 3 ) adapted to be triggered with the current from the trigger capacitor (C 2 ) flowing via the zener diode (V 5 ), wherein the cathode of the auxiliary thyristor (V 3 ) is connected to the gate of the thyristor (V 1 ) for triggering the thyristor (V 1 ) with the current from the trigger capacitor (C 2 ) flowing via the auxiliary thyristor (V 3 ) for using the thyristor (V 1 ) in a diode mode.