A driving apparatus is provided including brightness/contrast control means (5) for receiving video input data for tuning the video input data in accordance with external adjustment data and for outputting tuned video data. First power measurement means (10) measure a power level of the tuned video data and supply a first power level. Second power measurement means (11) measure a power level of the video input data and supply a second power level. Finally, generator means (12) transfer a third power level comprised between the first power level and the second power level or equal to them to the data processing means (6, 7, 8, 9) as power control information. Data processing means (6, 7, 8, 9) process the tuned video data on the basis of power control information and control the plasma display panel (1) respectively. Thus, the number of gray levels can be increased and the picture quality improves significantly.