A digital control loop within power switchers and the like includes a sliding error sampler pulse width modulation timing variably setting a number of clock cycles relative to a digital pulse width modulator output trailing edge for loading control variables for a filter. A computation time for the proportional-integral-derivative filter is predicted based on an average for previous digital pulse width modulator outputs, computed within the integral path for the previous loop iteration. A margin is added to accommodate transient conditions accelerating the trailing edge of the digital pulse width modulator output, either fixed or variable depending on the previous iteration pulse width.