For the laptop voltage regulators, not only the heavy load efficiency, but also the light load efficiency is very important for thermal point and for the battery running time. So far, to increase the heavy load efficiency, the two stage structure is proposed and to increase the light load efficiency of this two stage voltage regulators, the adaptive bus voltage positioning (ABVP) control concept is proposed. In this paper, the ABVP control structure is proposed. For the proper design of this system, the small signal model is derived and the stability analysis is performed. And the simulation and experiment results verify this analysis.