Patent ID: 6191568
Filing Date: 2001-02-20
Classification: H02M,H05B,Y02B

Abstract:
A power control unit for connection between a source of power and a load, and for control of power supplied to the load, which source when connected to the power control unit provides power to the power control unit at an input voltage, the power control unit comprising:a power supply circuit connectable to the power source for providing output power at controllably variable output voltage values over a range of output voltage values;output voltage selection means for setting the output voltage value at which output power is for the time being supplied to the load;a power supply driver circuit connected to and for driving the power supply circuit to provide output power at an output voltage value for the time being selected; anda controller responsive to the output voltage selection means and coupled to the driver circuit for controlling the driver circuit to drive the power supply circuit to supply power at a set high voltage to the load for a period of time T.sub.Hi starting upon the occurrence of a high-power start condition and ending upon the occurrence of a high-power end condition, and to drive the power supply circuit to supply power at a set low voltage to the load for a later period of time T.sub.Lo starting upon the occurrence of a low-power start condition and ending upon the occurrence of a low-power end condition,the controller during a transition period following time period T.sub.Hi and preceding time period T.sub.Lo controlling the driver circuit to drive the power supply circuit so as to provide a series of selected output voltage values at which the power supply circuit provides output power to the load, said series of selected output voltage values diminishing controllably from the set high output voltage to the set low output voltage in accordance with selected characteristics of the load.