The buck-boost dc-dc switching converter (one that provides a constant output voltage regardless of whether the unregulated input voltage is greater than or less than Vout) presents a greater design challenge than a simple buck or boost. Of the various circuit topologies available, the H-bridge presents the most attractive solution. This Basics of Design derives the H-bridge from its classic roots, explains the differences among alternative topologies, and describes the optimum implementation of the H-bridge buck-boost. - Intersil
