Improved current controllers of the present invention provide efficient, low noise, precision current control for devices having such operational requirements. The current controllers are characterized by a PWM regulator operably connected to a linear regulator. The PWM regulator regulates a voltage drop across the linear regulator, wherein the voltage provided to the linear regulator is greater than the output voltage of the linear regulator by a controlled operating margin. The PWM provides efficient power conversion and minimizes waste power dissipation in the linear regulator. The linear regulator, in turn, provides low noise, precision current drive to the connected load.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 This invention was made with Government support under Contract DE-AC0576RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.