A current source apparatus for reducing interference with noise is
provided. The current source apparatus includes a controllable current
source and a feedback controller. The controllable current source
provides an output current according to a control signal and produces a
feedback signal according to the output of the controllable current
source. The feedback controller is coupled to the controllable current
source for receiving the feedback signal, and the feedback controller
adjusts the control signal based on the feedback signal and outputs the
control signal for controlling the controllable current source to output
a stable output current.