Patent ID: 7259476
Filing Date: 2007-08-21
Classification: H02J,H02M

Abstract:
1. A power supply for providing alternating current (AC) and direct current (DC) to a plurality of loads, the power supply comprising: a transformer having first, second, third and fourth windings; an AC input for receiving AC power from an external source, the AC input connected across the first winding through a backfeed relay; an AC output connected across the first winding and connected to the AC input through the backfeed relay; an inverter connected across the second winding; a pair of battery terminals connected between the inverter and a center tap of the second winding; a charger connected across the third winding, the charger coupled to the pair of battery terminals; a rectifier connected across the fourth winding; a DC output connected to the rectifier through a DC/DC regulator; and, a controller coupled to the AC input, the backfeed relay, the inverter and the charger, wherein when AC power is received at the AC input the power supply operates in a normal mode wherein the controller closes the backfeed relay such that: the AC output receives AC power from the AC input through the backfeed relay; the rectifier receives AC power from the AC input through the backfeed relay and the transformer; and, the DC output receives DC power from the rectifier through the DC/DC regulator, and when AC power is not received at the AC input the power supply operates in a backup mode wherein the controller opens the backfeed relay and causes the inverter to operate in push-pull fashion such that: DC power received at the pair of battery terminals is converted to AC power and provided to the second winding through the inverter; the AC output receives AC power through the transformer; the rectifier receives AC power through the transformer; and, the DC output receives DC power from the rectifier through the DC/DC regulator.