A multi-mode adaptive control scheme to achieve high conversion efficiency over wide load range is presented in this paper. The presented controller results in improved efficiency while operating at a fixed switching frequency which guarantees maintained steady-state and dynamic performance at all load conditions. This is achieved by operating in three or more different modes in a reconfigurable topology structure as a function of the load to achieve a reduced total conversion loss which reduces energy usage and extends battery life. Theoretical analysis for the proposed control scheme and comparison with state of the art schemes are presented and validated with a 1.5V /50W proof of concept experimental prototype results.