Patent ID: 7768801

Claim:
A current resonant DC-DC converter of multi-output type, comprising: first and second switching elements connected in series to a DC power source, a series circuit which comprises current resonance capacitor, an inductance and a primary winding of a transformer connected in parallel to said first or second switching element, a first rectifying smoother connected to a first secondary winding of the transformer, a second rectifying smoother connected to a second secondary winding of the transformer, an output-regulatory switching element connected between said secondary winding of the transformer and a smoothing capacitor in the second rectifying smoother, and an output control circuit for controlling the on-off operation of the output-regulatory switching element based on voltage from the smoothing capacitor in the second rectifying smoother, wherein said output control circuit detects rising pulse or falling pulse in voltage on said second secondary winding of the transformer to control the on-off operation of the output-regulatory switching element in synchronization with switching frequency of said first or second switching element, and wherein the on-off operation of the first and second switching elements causes resonance current to flow through the current resonance capacitor, inductance and primary winding of the transformer and the first or second switching element so that a first DC output voltage is provided from the first secondary winding of the transformer through the first rectifying smoother and simultaneously a second DC output voltage is provided from the second secondary winding of the transformer through the second rectifying smoother.