Semiconductor switch device having means for supplying control current to a control electrode

In a power path having two terminals and supplied with main current, a semiconductor switch device comprising:

• a semiconductor switch having two main current electrodes and a control electrode, one of the main current electrodes adapted to be connected to one of the two terminals of the power path, said semiconductor switch being rendered conductive across the main current electrodes when a forward current is supplied to the control electrode;
• a transformer having a core, a first winding, a second winding, a third winding, and a fourth winding, the first winding having one end connected to the other of the main electrodes of said semiconductor switch and adapted to have the other end connected to the other of the two terminals of the power path, main current flowing through the first winding producing a first magnetomotive force, the second winding being connected between the one of the main electrodes and the control electrode of said semiconductor switch, whereby a forward current responsive to the main current flowing through the first winding is supplied from the second winding to the control electrode, the fourth winding being connected between the one of the main electrodes and the control electrode of said semiconductor switch;
• and
• electrical pulse applying means for applying an electrical pulse to the third winding of said transformer, the resulting current flowing through the third winding producing a second magnetomotive force opposite to the first magnetomotive force, whereby a forward current responsive to the current flowing through the third winding is supplied from the fourth winding to the control electrode.