Patent ID: 7944085

Claim:
A multiple output switching power source apparatus comprising: a first switching element and a second switching element being connected in series between output terminals of a DC power source; a first series resonant circuit connected in parallel with the first switching element or the second switching element and having a first current resonant capacitor, a first resonant reactor, and a primary winding of a transformer those are connected in series; a first rectifying-smoothing circuit configured to rectify and smooth a voltage generated by a secondary winding of the transformer; a second series resonant circuit connected in parallel with the secondary winding of the transformer and having a second current resonant capacitor and a second resonant reactor those are connected in series; a second rectifying-smoothing circuit configured to rectify and smooth a voltage of the second series resonant circuit; and a control circuit configured to determine an ON period of the first switching element according to a voltage obtained from any one of the first rectifying-smoothing circuit and second rectifying-smoothing circuit, determine an ON period of the second switching element according to a voltage obtained from the other of the first rectifying-smoothing circuit and second rectifying-smoothing circuit, and alternately turn on/off the first switching element and second switching element.