Patent ID: 7782639

Claim:
A method of converting power from a source at an input voltage for delivery to a load at a controlled output voltage, where the input voltage may vary between a high line voltage and a low line voltage, comprising: providing a converter array having an input, an output, and a first input cell and a second input cell, each input cell having a respective number, P x , of turns and an output cell having a respective number, S x , of turns; providing magnetic coupling between the turns to form a transformer common to the cells, wherein the turns of the first and second input cells form first and second primary windings and the turns of the output cell forms a secondary winding; and providing a circuitry to operate the cells in a series of converter operating cycles, each converter operating cycle including: (a) transferring energy from the input to the transformer via the primary windings during an energy-storage phase characterized by (i) an average value of primary current flowing in the primary windings, the average value of primary current having a first polarity, (ii) by an average increase in energy stored in the transformer, the averages being taken over the duration of the energy-storage phase and being greater than zero; (b) transferring energy from the transformer via said secondary winding to the load during an energy-transfer phase characterized by an average decrease in energy stored in the transformer, the average being taken over the duration of the energy-transfer phase and further characterized by a complete or a substantial absence of temporal overlap with the energy-storage phase; configuring the input cells in a parallel connection for operation at the low line voltage and in a series connection for operation at the high line voltage; and providing circuitry to control the output voltage.