A method and a control apparatus for driving a lamp (14) in a lighting system, in particular a lamp laving a fast response to a change of an amount of energy supplied through the lamp, in which a device controller 8 is connected with the lamp (14) The device controller (8) receives data values from a system controller (2) to change a light output level of the lamp (14). Upon receiving a data value which is different from a previously received data value the device controller calculates additional data values and distribute the additional data values in a following, time interval to smoothen a transition between different light output levels of the lamp (14).