Patent ID: 7038594

Claim:
A circuit for powering a device based on a command signal, comprising: a voltage measurement device adapted to provide a device voltage measured across the device; a current amplifier receiving the command signal and connected to the device, said current amplifier capable of linearly regulating current flowing through the device; and a power supply having a supply voltage signal connected to the device, said supply voltage signal being regulated by said power supply based on said voltage measurement device, wherein said voltage measurement device is coupled to said current amplifier and said power supply and power dissipation in said current amplifier is minimized by varying said supply voltage signal based on said voltage measurement device, and wherein said voltage measurement device further comprises a voltage biasing circuit receiving said device voltage and providing a biased voltage signal to a control input of said power supply, said biased voltage signal set by said voltage biasing circuit such that said supply voltage signal produced by said power supply is regulated to approximately equal said device voltage plus a predetermined bias voltage.