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

Claim 1

Monolithic integrated switching system to short-circuit a load (1) connected to a source (U 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 1 , C 2 ) connected to said collector zone, and located at opposite sides of the base zone (24), one collector electrode (C 1 ) being connected to the source (U B ) and the other collector electrode (C 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 1 , E 2 , E 3 ), and a common external terminal connection (E) connected to all said emitter terminals (E 1 , E 2 , E 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 1 , B 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 1 , B 2 ) connected to the base zone (24).