Patent ID: 8169224

Claim:
A power circuit comprising: a power transistor configured to feed a load current to a load; a measuring transistor for coupling out a measurement current dependent on the load current; at least two coupling transistors for dividing the measurement current into an internal measurement current and an external measurement current, wherein the external measurement current can be fed to an external evaluation circuit, and the internal measurement current is fed to an internal evaluation circuit for evaluation, wherein the at least two coupling transistors comprise a first coupling transistor configured to conduct the external measurement current, a second coupling transistor configured to conduct the internal measurement current, a third coupling transistor and a measuring device configured to determine a coupled nature of the external evaluation circuit to the power circuit, wherein the third coupling transistor is coupled to the measuring transistor if the measuring device determines a non-coupled state in which the external evaluation circuit is not coupled to the power circuit, and wherein the third coupling transistor is decoupled from the measuring transistor if the measuring device determines a coupled state in which the external evaluation circuit is coupled to the power circuit.