A circuit (100, 200, 300, 400) for providing a regulated output voltage (Vout), the circuit comprising: a variable frequency oscillator (102, 202, 302, 402); a control circuit configured and arranged to adjust an oscillation frequency of the variable frequency oscillator in response to a feedback signal (Vfb) indicating the regulated output voltage; a charge pump (104, 204, 304, 404) having a control input coupled to an output of the variable frequency oscillator and configured to charge one or more energy storage elements in response to the output of the variable frequency oscillator to produce a voltage signal; a plurality of output stages (112, 113, 212, 213, 312, 313, 412, 413), each output stage having an input driven by the voltage signal and configured and arranged to drive the regulated output voltage at the output node in response to respective enable signals (En) provided to the output stages; and an enable control circuit configured and arranged to provide the respective enable signals, characterised in that the control circuit comprises: a replica output stage (110, 210, 310, 410), configured to produce a feedback voltage proportional to the regulated output voltage, the replica output stage having an input driven by the voltage signal; and a difference amplifier (106, 206, 306, 406) having a first input coupled to an output of the replica output stage, a second input coupled to a reference voltage (vref), and an output coupled to a control input of the variable frequency oscillator. a variable frequency oscillator (102, 202, 302, 402); a control circuit configured and arranged to adjust an oscillation frequency of the variable frequency oscillator in response to a feedback signal (Vfb) indicating the regulated output voltage; a charge pump (104, 204, 304, 404) having a control input coupled to an output of the variable frequency oscillator and configured to charge one or more energy storage elements in response to the output of the variable frequency oscillator to produce a voltage signal; a plurality of output stages (112, 113, 212, 213, 312, 313, 412, 413), each output stage having an input driven by the voltage signal and configured and arranged to drive the regulated output voltage at the output node in response to respective enable signals (En) provided to the output stages; and an enable control circuit configured and arranged to provide the respective enable signals, characterised in that the control circuit comprises: a replica output stage (110, 210, 310, 410), configured to produce a feedback voltage proportional to the regulated output voltage, the replica output stage having an input driven by the voltage signal; and a difference amplifier (106, 206, 306, 406) having a first input coupled to an output of the replica output stage, a second input coupled to a reference voltage (vref), and an output coupled to a control input of the variable frequency oscillator. a replica output stage (110, 210, 310, 410), configured to produce a feedback voltage proportional to the regulated output voltage, the replica output stage having an input driven by the voltage signal; and a difference amplifier (106, 206, 306, 406) having a first input coupled to an output of the replica output stage, a second input coupled to a reference voltage (vref), and an output coupled to a control input of the variable frequency oscillator.