Patent ID: 7358713

Claim:
A constant voltage source comprising: an output current control element for adjusting an output voltage of the constant voltage source by varying its output current; a control circuit for acquiring a measure for an actual value of the output voltage and for processing the actual value to a control signal for the control of the output current control element; and a limiting circuit for limiting the output current to a predefined maximum value by acting on the control signal, the predefined maximum value being independent of the actual value of the output current; wherein the limiting circuit has a first pair having a first transistor and a second transistor and a second pair comprising a third transistor and a fourth transistor, wherein the first transistor and the fourth transistor have a first conductivity type, and the second transistor and the third transistor have a second conductivity type, wherein operating current paths of the first pair are in series between a reference current source and a supply potential, wherein operating current paths of the second pair are integrated in series into the control branch, wherein control terminals of the first and fourth transistors and of the second and third transistors, respectively, are connected to one another, and wherein control terminals of the first and fourth transistors are connected to the reference current source, and control terminals of the second and third transistors are connected to a first voltage source.