A drive unit for closing a leaf of a door or a window comprises an energy accumulator for providing a closing force for closing the leaf, a damping device which counteracts the closing force and has an electric motor which can be operated as a generator and can be coupled to an actuating element of the drive unit, and a control device for controlling the electric motor. The control device is designed to determine a nominal path curve which indicates a position of the leaf or a closing speed of the leaf in dependence upon time, and to perform the control of the electric motor in order to damp the closing movement of the leaf on the basis of the established target path curve.