In this paper, a mathematical description of the control method on the basis of difference correction [1] applying to sampled-data systems is considered. The difference correction is an efficient way to improving the dynamic characteristics of the pulse power converters, which work is described by difference equations. Proposed method allows transforming a difference equation so that the roots of the characteristic equation become equal to zero. Herewith the maximum speed of convergence of transient to a steady value in the field of it's environ under perturbations of system parameters is achieved. Using the example of a system for stabilizing the load current of a buck converter it is shown that the transient is completed within two or three periods.