Switched mode power supply and method of operating a switched mode power supply

A switched mode power supply comprising a switched mode converter and a controller for controlling the switched mode converter, the switched mode converter being provided for converting an input voltage to an output voltage and including:

• on a primary side, a primary winding and a controllable switch based circuitry connecting the input voltage over the primary winding;
• and
• on a secondary side, a secondary winding coupled to the primary winding, and a capacitive element connected over the secondary winding, wherein the output voltage is obtained as the voltage over the capacitive element, wherein:
• the primary winding comprises a first winding portion and at least one further winding portion;
• the switch based circuitry comprises controllable switches capable of switching between a first operation state wherein the input voltage is connected only over the first winding portion and at least a second operation state wherein the input voltage is connected over the first and the at least one further winding portions, thereby enabling switching between two different transformer ratios;
• and
• the controller is (i) configured to monitor the output voltage of the switched mode converter and (ii) operatively connected to the controllable switches to control the controllable switches to switch between the first and the at least second operation states in response to the monitored output voltage.