Abstract: A power backup processor and a method of operating the power backup processor suitable for a single-phase AC power supply and with a higher efficiency, at least when the critical load is fed with the single-phase AC power supply, while having a high availability and quality of voltage supply. This can avoid the drawbacks related to high DC voltages.

Abstract: The invention concerns a dc-to-dc converter controlled by a rectangular signal comprising an input for a direct voltage source (VDC), a transformer comprising a primary coil (1) connected to the direct voltage source (VDC) and a D2 secondary coil (2), a single switch (S) series-connected with the primary (1) and the direct voltage source (VDC), an output comprising the transformer secondary (2) and at least a tertiary coil (3) located in the proximity of the primary (1) and secondary (2) coils at the transformer core series-connected with a first diode (D1).