Abstract: An un-interruptible power supply coupled to a dc input voltage node, having a mode control circuit to monitors the input voltage and to provide a mode selection signal to indicate that the input voltage is above a predetermined level. A high frequency transformer has a primary winding, an output winding and a charger winding. A battery is referenced to a third reference potential node. An input inverter transfers power from the dc input voltage to an output rectifier and to an adaptive converter to charge a battery. The output rectifier and filter provides the output dc voltage referenced to the second reference potential node. The adaptive converter referenced to the third reference potential transfer power from the battery to the transformer charger winding to provide the output dc voltage source.

Abstract: An un-interruptible power supply coupled to a dc input voltage node, having a mode control circuit to monitors the input voltage and to provide a mode selection signal to indicate that the input voltage is above a predetermined level. A high frequency transformer has a primary winding, an output winding and a charger winding. A battery is referenced to a third reference potential node. An input inverter transfers power from the dc input voltage to an output rectifier and to an adaptive converter to charge a battery. The output rectifier and filter provides the output dc voltage referenced to the second reference potential node. The adaptive converter referenced to the third reference potential transfer power from the battery to the transformer charger winding to provide the output dc voltage source.

Abstract: A boost-input backed-up uninterrupted power supply provides an uninterrupted output voltage to a load. The backed-up power supply has an input rectifier and filter for converting an input voltage source voltage into at least an unregulated positive dc voltage source, and an unregulated negative dc voltage source. Batteries provide respective positive and negative battery voltages at corresponding positive and negative battery output terminals. A diode isolates the unregulated positive and negative dc voltage sources from their respective battery voltages for unregulated voltage source values equal to or greater than their respective battery voltages and clamps the unregulated dc voltage values to their respective battery voltages in response to loss of the sinusoidal input voltage source. A pair of boost regulators receives power from the unregulated positive and negative dc voltage sources and provide positive and a negative regulated dc voltage with respect to the return.