A thyristor protected against breakover firing is disclosed which has a region which, in comparison to the remaining semiconductor body, has a lower breakdown voltage. This region is provided with an auxiliary electrode and is separated from the remaining semiconductor body by a trench. Upon onset of the avalanche breakdown in the blocking direction, a voltage greater by 0.5 V, compared to the first emitter electrode, can build up at the auxiliary electrode without the thyristor firing. The auxiliary electrode is connected via a resistor with the first emitter electrode of the thyristor. In addition, between the auxiliary electrode and the control electrode a breakover element is interconnected which conducts at a given voltage drop across the resistor and initiates the firing process of the thyristor.
The present invention relates to a component protecting against electric overloads likely to occur on a conductor in series with which is placed a detection resistor. The component includes a first cathode-gate thyristor and a second anode-gate thyristor, of the gate current or forward break-over type. The anode region of the first thyristor, formed on the lower surface side, is separate from the isolating wall surrounding the thyristor and the rear surface of the isolating wall is coated with a portion of an insulating layer.
