The feedback regulation of DC-to-DC power supplies is, broadly speaking, accomplished through either PWM feedback strategies, or by inducing appropriate stabilizing sliding regimes. PWM control of these devices is treated in several books, among which we cite [117,238]. The topic has been also extensively treated, among many others, by the third author an collaborators in [244,249], where emphasis has been placed in using advanced nonlinear feedback control design techniques for the regulation of average PWM models of the various converters.