Abstract: A plural output power supply comprises a converter transformer having a first primary winding and first and second secondary windings. A first DC output circuit is driven by the first secondary winding and comprises a first series rectifier, a first series inductor wound on a first core and a first parallel capacitor. A second DC output circuit is driven by the second secondary winding and comprises a second series rectifier, a second series inductor wound on a second core and a second parallel capacitor. A sense transformer or series resistor senses a current in the first primary winding of the converter transformer. Circuitry subtracts the current in the second secondary winding from current sensed from the primary winding. If the first DC output is used to drive the stable load and the second DC output is used to drive the noisy load, the difference in the two currents represents the stable current and is used to control the drive to the primary of the converter transformer.

Abstract: A boost voltage converter is combined with any DC-DC converter to provide a power system with significant overall power efficiency improvement in applications requiring continuous operation through low line transient levels. The boost converter is normally in a standby mode and only operates when the input DC voltage drops below a predetermined minimum steady state voltage. During steady state operation, a simple, efficient feedthrough of the DC current directly to the DC-DC converter is provided. Efficiency improvements in the combination of boost converter and DC-DC converter result from the reduction of the effective transient range seen by the DC-DC converter, allowing the DC-DC converter components to be designed and selected to significantly reduce their power dissipation during nontransient input steady-state operation.