DC2151A: 1.8 ~ 5V, 3 ~ 19V in, Solar Charger

Demonstration Circuit DC2151A is a nano-power buck/boost DC/DC with energy harvesting battery charger featuring the LTC®3331. 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.

A 10mA shunt allows simple battery charging with harvest energy while a low battery disconnect function protects the battery from deep discharge. A supercapacitor balancer is also integrated, allowing for increased output storage.

Voltage and current settings for input and output as well as the battery float voltage are programmable via pin-strapped logic inputs.