Patent ID: 7260103

Claim:
A method for supplying electrical power to a utility devices, comprising the steps of: (a) providing a controlled transistor switching circuit comprising at least one bipolar transistor having a drive input port comprising a base and a first and at least a second current drive current source in series with a first and second switch, respectively, coupled to said base, said switching circuit operative to couple respectively a plurality of different operational voltages to said utility device for respectively different modes of operation of said utility device; (b) determining an operational parameter of said utility device, said operational parameter associated with a present one said different modes of operation of said utility device; and based on a level of said operational parameter or said present mode of operation of said utility device, (c) selectively adjusting current handling capability of said controlled transistor switching circuit by controlling positions of said first and second switch to define a value of bias current used as base drive to drive said base of said transistor, and (d) causing said controlled transistor switching circuit to couple one of said respectively different operational voltages to said utility device.