Maxim describes various SMPS regulator topologies for battery powered systems. Isolated and non-isolated topologies are covered:
This tutorial presents an overview of regulator topologies for battery-powered equipment. The discussion covers linear regulators, charge pumps, buck and boost regulators, inverters, and flyback designs. The importance of peak current is explained, and schematics of each topology are shown.
Switch mode regulators for battery powered systems - [Link]