A circuit arrangement, comprising: a first branch (101, 103, 104) comprising: a terminal for a supply potential; a resistor of variable resistance; a bipolar transistor connected as a diode; a terminal for ground potential connected to the bipolar transistor; a second branch, comprising: a resistor of fixed resistance, the resistor of fixed resistance connected to the resistor of variable resistance of the first branch (101, 103, 104); another bipolar transistor connected as a diode, the terminal for ground potential connected to the other bipolar transistor; a control loop configured to reproduce a voltage drop at the resistor of variable resistance to a voltage drop at the resistor of fixed resistance, the control loop, comprising: a transistor disposed in the second branch; an amplifier having input terminals (-, +) connected to the resistors (131, 141) of the first and second branches (101, 103, 104; 102) and having an output terminal to control the transistor of the second branch, wherein the transistor is controlled such that the difference between the voltages at the input terminals (-, +) of the amplifier becomes substantially zero; a voltage shifter disposed in the first branch (101, 103, 104) and connected between the resistor of variable resistance and the bipolar transistor; and an output terminal connected to the bipolar transistor of the first branch (101, 103, 104) and another output terminal connected to the other bipolar transistor of the second branch, the output terminals configured to supply a differential voltage (VBE1, VBE2). a first branch (101, 103, 104) comprising: a terminal for a supply potential; a resistor of variable resistance; a bipolar transistor connected as a diode; a terminal for ground potential connected to the bipolar transistor; a terminal for a supply potential; a resistor of variable resistance; a bipolar transistor connected as a diode; a terminal for ground potential connected to the bipolar transistor; a second branch, comprising: a resistor of fixed resistance, the resistor of fixed resistance connected to the resistor of variable resistance of the first branch (101, 103, 104); another bipolar transistor connected as a diode, the terminal for ground potential connected to the other bipolar transistor; a resistor of fixed resistance, the resistor of fixed resistance connected to the resistor of variable resistance of the first branch (101, 103, 104); another bipolar transistor connected as a diode, the terminal for ground potential connected to the other bipolar transistor; a control loop configured to reproduce a voltage drop at the resistor of variable resistance to a voltage drop at the resistor of fixed resistance, the control loop, comprising: a transistor disposed in the second branch; an amplifier having input terminals (-, +) connected to the resistors (131, 141) of the first and second branches (101, 103, 104; 102) and having an output terminal to control the transistor of the second branch, wherein the transistor is controlled such that the difference between the voltages at the input terminals (-, +) of the amplifier becomes substantially zero; a transistor disposed in the second branch; an amplifier having input terminals (-, +) connected to the resistors (131, 141) of the first and second branches (101, 103, 104; 102) and having an output terminal to control the transistor of the second branch, wherein the transistor is controlled such that the difference between the voltages at the input terminals (-, +) of the amplifier becomes substantially zero; a voltage shifter disposed in the first branch (101, 103, 104) and connected between the resistor of variable resistance and the bipolar transistor; and an output terminal connected to the bipolar transistor of the first branch (101, 103, 104) and another output terminal connected to the other bipolar transistor of the second branch, the output terminals configured to supply a differential voltage (VBE1, VBE2).