A single-mode quasi constant frequency controller apparatus for controlling output voltage deviation during one or more load transients, the controller apparatus comprising: a converter receiving one or more operational control parameters; a load tracking modulator configured to receive sensory inputs representative of a capacitor current polarity, and to control one or more power transistors of the converter such that an inductor current matches a load current cycle and reconstructs a desired inductor current ripple by splitting both an on-time for inductor charging and an off-time for inductor discharging into a current correction phase (CCP) and a ripple reconstruction phase (RRP), the load tracking modulator communicating the one or more operational control parameters for controlling the one or more power transistors.