A driving circuit comprising: a converter comprising: an input to receive a supply voltage (Vrec) with a cyclic ripple having peak portions and valley portions; a switch mode power converter circuit to convert the supply voltage, including an energy storage component and a main control switch; an output; and a current sensor for sensing an output current delivered at the output and generating a sensed current signal; a control circuit to control a switching of the main control switch of the converter circuit, wherein the energy storage component is adapted to discharge to provide a regulated DC current at the output upon the switching of the main control switch; and a modulation circuit to apply a time-varying offset to the control circuit to modulate the regulated current thereby controlling the voltage across the energy storage component, characterized in that the modulation circuit comprises a ramp circuit for generating a time-varying ramp signal for combination with a static reference current signal (Vref) to generate a modulated reference current signal (Vref) and the control circuit comprises a comparator circuit for comparing the sensed current signal with the modulated reference current signal (Vref) and an output of the comparator is adapted to provide a current feedback signal for the control circuit so that the time-varying offset is adapted to ensure a margin of the voltage across the energy storage component above the supply voltage. a converter comprising: an input to receive a supply voltage (Vrec) with a cyclic ripple having peak portions and valley portions; a switch mode power converter circuit to convert the supply voltage, including an energy storage component and a main control switch; an output; and a current sensor for sensing an output current delivered at the output and generating a sensed current signal; an input to receive a supply voltage (Vrec) with a cyclic ripple having peak portions and valley portions; a switch mode power converter circuit to convert the supply voltage, including an energy storage component and a main control switch; an output; and a current sensor for sensing an output current delivered at the output and generating a sensed current signal; a control circuit to control a switching of the main control switch of the converter circuit, wherein the energy storage component is adapted to discharge to provide a regulated DC current at the output upon the switching of the main control switch; and a modulation circuit to apply a time-varying offset to the control circuit to modulate the regulated current thereby controlling the voltage across the energy storage component, characterized in that the modulation circuit comprises a ramp circuit for generating a time-varying ramp signal for combination with a static reference current signal (Vref) to generate a modulated reference current signal (Vref) and the control circuit comprises a comparator circuit for comparing the sensed current signal with the modulated reference current signal (Vref) and an output of the comparator is adapted to provide a current feedback signal for the control circuit so that the time-varying offset is adapted to ensure a margin of the voltage across the energy storage component above the supply voltage.