Power-supply/battery back-up power supply/battery charger combination

Claim 1

A combination power supply-battery backup power supply-battery charger, comprising: an AC power source, including a transformer means for providing a predetermined AC voltage; a rectification means placed in an AC circuit with said AC power source for providing a unidirectional current in a DC branch within said AC circuit; a regulating means positioned in said DC branch for providing a regulated DC output, said regulating means being characterized by a low input to output ratio such that the minimum allowable input voltage to said regulating means is less than or equal to the output voltage of said regulating means plus two volts; a DC power source comprising a battery within said DC branch; said battery being characterized by a discharge voltage which is less than or equal to the output voltage of said regulating means plus two volts; and a battery charging circuit positioned in said unidirectional branch in parallel with said regulating means, said battery charging circuit comprising said battery within said circuit, said battery being further characterized by a charging voltage which is less than or equal to one hundred twenty-five percent (125%) of said battery discharge voltage, whereby the AC voltage supplied from the transformer means is determinable at a voltage greater than the battery charging voltage, yet at a very low voltage relative to the output voltage of the regulating means; and whereby the relatively low voltage from the transformer means simultaneously serves as input voltage to the regulating means for supply to a load and as charging voltage to charge the battery with the charging circuit, and the battery provides voltage within defined limits as input voltage to the regulating means in the absence of power from the AC power source, all with low heat loss and high efficiency.