Apparatus and associated methods relate to continuously providing power to a load throughout an interruption of a power source. While the power source is providing power, a converter is exciting a primary winding of a transformer. A load winding of the transformer delivers power to a load connected thereto, and a holdup winding provides power to a holdup circuit, which stores energy for use when the power source is interrupted. A turns ratio of the holdup winding to the primary winding is greater than one so that the energy stored by the holdup circuit is at a voltage that is greater than or equal to the voltage used for exciting the primary windings. If the voltage used for exciting the primary windings falls below a predetermined threshold, a one-shot controls the transfer of energy stored in the holdup circuit to a storage capacitor supplying current to the primary windings.