Demonstration Circuit DC2151A is a nanopower buckboost DC/DC with energy harvesting battery charger featuring the LTC3331. The LTC3331 integrates a high voltage energy harvesting power supply plus a DC/DC converter powered by a rechargeable cell battery to create a single output supply for alternative energy applications. The energy harvesting power supply, consisting of an integrated low-loss full-wave bridge with a high voltage buck converter, harvests energy from piezoelectric, solar or magnetic sources. The rechargeable cell input powers a buck-boost converter capable of operating down to 1.8V at its input. Either DC/DC converter can deliver energy to a single output. The buck operates when harvested energy is available, reducing the quiescent current drawn on the battery to essentially zero. The buck-boost takes over when harvested energy goes away.