Patent ID: 7550872

Claim:
An uninterruptible power supply comprising an input power supply and a main power circuit providing a DC output voltage and being connected to the input power supply, said input power supply providing an AC voltage, wherein said uninterruptible power supply further comprises a current sensor connected in series between the power supply and the main power circuit and the current sensor configured to continuously sense a total current received from said input power supply; and at least one accessory circuit connected to receive the AC voltage from the input power supply and being connected in parallel with the main power circuit, said connection being between said current sensor and said main power circuit, said current sensor measuring the total current drawn from said input power supply and provided to said main power circuit and to said at least one accessory circuit; wherein said total current is in-phase with said input power supply voltage and wherein said total current received from said input power supply comprises an inductor current and an accessory circuit current.