<p>A digital controller (DC) for a DC-DC converter which supplies an output voltage (Vo) to a load (LO). The digital controller (DC) comprises a digital comparator (DCOM) to compare the output voltage (Vo) or a tapped- in output voltage with a reference voltage (VR) to obtain a digital error signal (E). A step-size controller (SZC) receives the digital error signal (E) and controls a step size of the digital error signal (E) to obtain a step size controlled error signal (kE) having a larger step size during a transient condition of said converter than in a steady state condition of said converter. A switch controller (DSC) for receiving the step size controlled error signal (kE) for controlling at least one switching element (Sl, S2) of said converter for regulating the output voltage (Vo).</p>
