Switching system to short-circuit a load with minimum residual voltage

Monolithic integrated switching system to short-circuit a load (1) connected to a source (U.sub.B) having a controlled semiconductor switch having its main switching terminals connected in parallel with the terminals (2, 3) of the load (1) and having a control terminal (B) effecting opening and closing of the switch under control of a control signal applied to the control terminal,

• wherein the controlled semiconductor switch comprises a monlithic integrated vertical transistor (405) having a base zone (24), a collector zone, two collector electrodes (C.sub.1, C.sub.2) connected to said collector zone, and located at opposite sides of the base zone (24), one collector electrode (C.sub.1) being connected to the source (U.sub.B) and the other collector electrode (C.sub.2) being connected to the other terminal (2) of the load, a conductive layer (30) beneath the collector zone, and an emitter zone (26), sub-divided into a plurality of n spatially separated emitter sub-zones (26a, 26b, 26c), n being greater than one, each sub-zone having a metallization forming an emitter terminal (E.sub.1, E.sub.2, E.sub.3), and a common external terminal connection (E) connected to all said emitter terminals (E.sub.1, E.sub.2, E.sub.3) and galvanically connected to one terminal of the load;
• the base zone (24) of the monolithic integrated circuit having n-1 terminal connections (B.sub.1, B.sub.2), each being located between two adjacent emitter sub-zones (26a, 26b;
• 26b, 26c);
• a common external base terminal (B):
• and individual coupling resistors (50, 51), connected between the common base terminal (B) and each one of the separate base terminal connections (B.sub.1, B.sub.2) connected to the base zone (24).