A pixel circuit comprising a photodetector pixel arrangement and a voltage regulating circuit adapted for applying a target voltage to the pixel arrangement, the photodetector pixel arrangement comprising at least one pixel comprising a photodetector, an integrator for accumulating a signal from the photodetector, and a source following output transistor for amplifying the integrated signal, wherein the integrator comprises a capacitor between a gate of the source following output transistor and the ground, the photodetector pixel arrangement comprising a current source for biasing the source following output transistor by applying a readout current through the source following output transistor, the voltage regulating circuit comprising an amplifier, a replica transistor, and a replica current source, wherein - the gate of the replica transistor is electrically connected with the output node of the amplifier, and the output node of the amplifier is electrically connected with the pixel arrangement for providing the target voltage, - the drain of the replica transistor is electrically connected, during operation, with a power supply, - and the source of the replica transistor is electrically connected with the negative input node of the amplifier, and with the replica current source, wherein the voltage regulating circuit is arranged such that, during operation, a predefined reference voltage is applied to the positive input node of the amplifier, characterized in that the replica transistor is dimensioned substantially the same as the output transistor of the at least one pixel and that, during operation, the replica current source provides substantially the same current through the replica transistor as the readout current and that, during operation, the target voltage is supplied to the drain of the source following transistor of the pixel, or of each pixel of the pixel arrangement. the photodetector pixel arrangement comprising at least one pixel comprising a photodetector, an integrator for accumulating a signal from the photodetector, and a source following output transistor for amplifying the integrated signal, wherein the integrator comprises a capacitor between a gate of the source following output transistor and the ground, the photodetector pixel arrangement comprising a current source for biasing the source following output transistor by applying a readout current through the source following output transistor, the voltage regulating circuit comprising an amplifier, a replica transistor, and a replica current source, wherein - the gate of the replica transistor is electrically connected with the output node of the amplifier, and the output node of the amplifier is electrically connected with the pixel arrangement for providing the target voltage, - the drain of the replica transistor is electrically connected, during operation, with a power supply, - and the source of the replica transistor is electrically connected with the negative input node of the amplifier, and with the replica current source, - the gate of the replica transistor is electrically connected with the output node of the amplifier, and the output node of the amplifier is electrically connected with the pixel arrangement for providing the target voltage, - the drain of the replica transistor is electrically connected, during operation, with a power supply, - and the source of the replica transistor is electrically connected with the negative input node of the amplifier, and with the replica current source, wherein the voltage regulating circuit is arranged such that, during operation, a predefined reference voltage is applied to the positive input node of the amplifier, characterized in that the replica transistor is dimensioned substantially the same as the output transistor of the at least one pixel and that, during operation, the replica current source provides substantially the same current through the replica transistor as the readout current and that, during operation, the target voltage is supplied to the drain of the source following transistor of the pixel, or of each pixel of the pixel arrangement.