The advantage of having a digital solution, with the use of a dedicated microcontroller, is given by the possiblity to manage lamps with different power levels keeping the same circuit architecture. Two different approaches can be implemented:
Full digital ballasts are completely managed by a microcontroller. The microcontroller manages both the high-voltage half bridge driver to manage the lamps and the low-voltage driver for the PFC pre-regulation.
A mixed digital ballast, where the microcontroller manages only a section of the ballast, usually the half bridge section, while for the PFC section an analog PFC controller is used.