A power supply with capacitive mains isolation, comprises a source of an input supply voltage developed between a first terminal and a second terminal. A first supply inductance is coupled to the first terminal, and a second supply inductance is coupled to a load circuit. A switch responsive to a periodic control signal applies the input supply voltage to the first supply inductance to generate a current in the first supply inductance at a first polarity, during a first portion of a period of the control signal when the switch is at a first switch state. A pair of capacitors operate to couple the first supply inductance to the second supply inductance during a second portion of the period of the control signal when the switch is at a second switch state. The pair of capacitors isolate the first and second terminals, respectively, from the second supply inductance at a range of frequencies that is lower than a frequency of the control signal. A first rectifier is coupled to the first supply inductance for preventing the first supply inductance current from changing polarity, during the second portion of the period.