There are questions battery charger designers must consider at the start of each new design. Does the system have a high input voltage supply? Are there high capacity batteries to charge? Does the input voltage range span above and below the battery voltage range? Furthermore, there are many markets without dedicated battery charging solutions such as: high series cell count battery stacks, presently there are no existing solutions for greater than four lithium cells; high input voltage applications, there are no existing solutions above 30V to 40V; buck-boost applications and isolated topologies (e.g. a flyback configuration). Available battery charging controllers are primarily limited to step-down or buck architectures. Finally, existing solutions charge multiple battery chemistries, some with onboard termination, however none provide the necessary performance features to solve all of the considerations outlined here. The LTC4000 has been introduced by Analog Devices to address these needs.