The invention relates to a control device (3) for a compressed air preparation device (1) of a vehicle (2), wherein the control device (3) outputs output signals for adjusting feed phases and regeneration phases of the compressed air preparation device (1), wherein a compressor (4) feeds compressed air via an air dryer having a desiccant (6a) into a compressed air reservoir (8) in a feed phase, and compressed air is fed out of the compressed air reservoir (8) through the air dryer (6) for drying the desicant (6a) in a regeneration phase. According to the invention, the control device (3) adjusts the regeneration phases depending on a current or future engine load and/or a current or future consumption of compressed air by the vehicle (2). Particularly in coasting phases, excessive drying of the desiccant to a low moisture can occur, in order to save fuel in later travel segments. Route-optimized regeneration of the desiccant as a function of engine load and/or utilization phases is also possible.