Patent ID: 8347120

Claim:
An input power unit for controlling power supplied to an electrical apparatus which is coupled to a direct current power supply, the input power unit comprising: input terminals adapted to be connected to a source of alternating current; a switch coupled to the input terminals; a control unit connected to provide control signals to the switch; a rectifier connected to the switch; a power management bus coupled to the control unit, the direct current power supply and the electrical apparatus, wherein: the rectifier comprises a pair of diodes, each having an anode and a cathode; the input terminals are coupled to respective anodes of each of the pair of diodes; the cathodes of the pair of diodes are coupled together and to a first input terminal of the direct current power supply; the switch is coupled to each of the anodes and to a second in gut tee the direct current power supply; and wherein: in response to energy management signals regarding the electrical apparatus provided on the power management bus, the control unit provides signals to the switch to provide changing amounts of alternating current to the rectifier, and the rectifier in response provides controlled amounts of direct current ranging from a maximum value to zero to the direct current power supply.