On load adaptive control of voltage regulators for power managed loads: Control schemes to improve converter efficiency and performance

Voltage regulator (VR) efficiency improvement especially at light load currents is important in many applications including those that are battery powered and have energy consumption constrains. However, controlled steady-state and dynamic performance should be maintained while improving efficiency. In this paper, an analytical study of VR losses and voltage ripple deviation is presented and discussed, yielding to proposed control technique, namely "pulse sliding" (PSL) control technique, which results in improved VR conversion efficiency with low and controlled voltage ripple and improved dynamic response. The proposed method and controller achieves the advantages of both variable frequency and fixed frequency controls and eliminates their disadvantages by utilizing information obtained from the inductor peak current, compensation error signal and capacitor current, resulting in an optimum nonlinear switching frequency modulation. PSL is compared to other control methods by both analysis and experiments. Experimental results highly agree with theoretical analysis.