US Patent 7924543 Current-limiting circuit with additional current path

A current-limiting circuit (100), which limits an electrical current from a voltage source to a consumer to a predetermined maximum current. A measuring resistor (110) is coupled into a current lead (103) between a circuit input (102) and a circuit output (104). A transistor (106) of the circuit is coupled into the current lead (103) with its collector-emitter path in series with the measuring resistor (110), and its base is connected to the current lead (103) through a series resistor (108). A shunt regulator (116) of the circuit has an anode, a reference input and a cathode, wherein the cathode is connected to the base of the transistor (106), and the anode and the reference input form a voltage tap across the measuring resistor (110). An additional, high-ohmic current path extends in parallel to the transistor (106) and includes a component connected reverse-biased having a diode characteristic and an auxiliary measuring resistor (120b), wherein the auxiliary measuring resistor (120b) is integrated in the voltage tap.