The present invention relates to a switched mode power supply with programmable digital control and to a power supply system comprising a plurality of switched mode power supplies. The input terminals and the output terminals of the switched mode power supply system are separated by an insulation barrier, and the switched mode power supply comprises a conversion stage having at least one switching element. The switching element of the conversion stage, as well as any switching elements of a possible pre-regulator, is digitally controlled by a programmable digital circuit. In one embodiment of the switched mode power supply, the programmable digital circuit is located on the primary side of the insulation barrier.