Patent ID: 7193496

Claim:
A power supply, comprising: a magnetic element which transforms a first input AC voltage and a second input AC voltage to output them as a first output AC voltage and a second output AC voltage; and a rectifying/smoothing circuit which rectifies and smoothes the first and the second output AC voltages, wherein the magnetic element includes: a magnetic core including an inner leg portion and a plurality of outer leg portions which share the inner leg portion, the plurality of outer leg portions each of which forms a loop magnetic path together with the inner leg portion; an input inner leg coil which is wound around the inner leg portion, the input inner leg coil into which the first output AC voltage is inputted; an output inner leg coil which is wound around the inner leg portion, and outputs the first output AC voltage; an input outer leg coil which is wound around the outer leg portion, the input outer leg coil into which the second input AC voltage is inputted; and an output outer leg coil which is wound around the outer leg portion, and outputs the second output AC voltage, the input outer leg coil is formed through connecting a first input outer leg coil portion wound around an outer leg portion of one loop magnetic path and a second input outer leg coil portion wound around an outer leg portion of another loop magnetic path in series, the output outer leg coil is formed through a first output outer leg coil portion wound around an outer leg portion of one loop magnetic path and a second output outer leg coil portion wound around an outer leg portion of another loop magnetic path in series, the winding directions of the first and the second input outer leg coil portions are in the same polarity direction, and the numbers of turns in the first input outer leg coil portion and the second input outer leg coil portion are equal to each other, the winding directions of the first and the second output outer leg coil portions are in the same polarity direction, and the numbers of turns in the first output outer leg coil portion and the second output outer leg coil portion are equal to each other, the input outer leg coil is wound around the outer leg portions so that magnetic fluxes generated in the plurality of outer leg portions by a current flowing through the input outer leg coil cancel each other out in the inner leg portion, and the output outer leg coil is wound around the outer leg portions so that magnetic fluxes generated in the plurality of outer leg portions by a current flowing through the output outer leg coil cancel each other out in the inner leg portion.