This paper introduces a novel power management architecture for battery powered portable applications, where ac-dc power adapters are used to charge the battery. The flyback-based system allows independent regulation of output bus voltage, irrespective of adapter output, and battery cell voltages. This architecture creates the flexibility to use a wide range of adapters to power the device while charging the battery cells. The effectiveness of the introduced architecture is verified on a 20-W, 100 kHz experimental prototype. Experimental results demonstrate tight output bus voltage regulation over a wide range of adapter-provided dc inputs and smooth transitions between adapter and battery powered modes of operation.