Fernspeiseschaltung in Kommunikationssystemen

摘要

In communications systems (KS), a DC voltage source (U) can be connected in each case with the aid of an electronic switch (FET) via windings (W1, W2) of an input transformer (Ü) and a connection line (ASL) to every communications terminal (KE). In the event of overload, the de-activation time, i.e. the time until the DC source (U) is de-activated, is controlled by the increase in the loop current (SL) with the aid of an integrator (IG) and a comparator (V). This produces short de-activation times in the event of substantial overload and consequently substantially reduced thermic load on the electronic switches (FET). This enables the use of electronic switches (FET) with a low maximum load.