A circuit, use, and method for operating a circuit is provided that includes a regulated first voltage source for providing a supply voltage at an output of the first voltage source for a subcircuit, an adjustable second voltage source for providing an output voltage to supply the subcircuit, and an evaluation circuit, which is connected to an output of the second voltage source and to a control input of the second voltage source and to the output of the first voltage source. Wherein the evaluation circuit is formed to adjust the output voltage of the second voltage source by means of a control signal at the control input of the second voltage source with evaluation of the supply voltage at the output of the first voltage source, and wherein the evaluation circuit and/or the second voltage source have a memory for storing values of the adjustment.