Power factor correction circuit for power supplies

Claim 1

A power factor correction circuit for an AC to low voltage DC power supply designed to be connected to a source of AC power, said circuit comprising a linear transformer having primary and secondary windings, said primary winding being arranged and adapted to be connected electrically in series with and between said source and said power supply, said primary winding having an inductance value selected to reduce odd harmonics from the line current drawn by said power supply as a load on said source of AC power, and a capacitor electrically connected in series with said secondary winding, the series connection of said capacitor and said secondary winding being arranged and adapted to be connected electrically in parallel with said power supply, between said primary winding and said power supply, said capacitor having a capacitance value selected to provide the reactive power demand of said power supply as a load on said source of AC power, and said secondary winding having a turns ratio relative to said primary winding selected to eliminate the loss of power supply operating line range caused by the voltage drop across said primary winding when said power factor correction circuit is electrically connected between said source of AC power and said power supply load, whereby to provide voltage regulation by said power supply proportional to substantially undistorted line input current from said source of AC power, with improved power factor, while overcoming the AC voltage drop across said primary winding that would otherwise reduce the operating line range of said power supply.