Abstract: Methods and apparatus for controlling the brightness level of a lamp in a backlit LCD display include primary and secondary controllers. The primary controller establishes the arc drive to the lamp to achieve the desired lamp brightness. The primary controller includes a desired brightness set-point as a first input, and a feedback signal corresponding to actual brightness detected at the lamp as a second input. The primary controller operates in real time, essentially adjusting the lamp arc drive instantaneously as a function of the detected brightness feedback signal. The secondary controller is employed to fine tune the control of the lamp by determining whether the desired brightness level may be achieved more efficiently. The secondary controller varies one or more parameters, such as temperature, within the lamp to achieve the optimum operating point of the lamp at the desired brightness level.