A system for providing a controllable current to a high intensity
discharge lamp is provided. The system includes a current controller that
is configured to receive input power and to provide an output current
waveform to the high intensity discharge lamp. This current causes a
discharge of light from the lamp. The output current waveform includes an
absolute value amplitude in each half cycle that is generally constant
during a first portion and that which increases non-linearly from the
generally constant amplitude to a peak amplitude during a second portion.