In a scanning backlight for an LCD display, several backlights (101, 102, 103, 10n) provide a precisely positioned dimming pulse corresponding to a transition point of the LCD screen. The dimming pulse must be variable with video synchronization frequency and dimming duty cycle, which is a performance intensive calculation. One microcontroller performing this operation is limited in scope. By using several ballast controllers (141, 142, 143, 14n), the solution is scalable, in that it is flexible if the number of backlights (101, 102, 103, 10n) changes. Additionally, by using several controllers (141, 142, 143, 14n), added functions can be performed by the ballast controllers (141, 142, 143, 14n).