One example discloses a wireless receiver circuit comprising: a wireless receiver unit having a first voltage power supply and providing an output as a stream of digital output bits; a parity check unit at the output; a control unit configured to derive a control output based on the difference between the parity check unit output and a target parity error rate; and a voltage regulator for providing the first voltage to the wireless receiver unit, in dependence on the control unit output wherein the voltage regulator implements a voltage overscaling function for the wireless receiver unit and is operable to overscale the first voltage in response to a parity error rate of less than 0.5 and to drive the first voltage to a predetermined maximum voltage value in response to a parity error rate of 0.5.