LTC3109/LTC4070 Unipolar Energy Harvester Charges Battery Backup

The LTC3109 is a highly integrated DC/DC converter ideal for harvesting surplus energy from extremely low input voltage sources such as TEGs (thermoelectric generators) and thermopiles. Its unique, proprietary autopolarity topology allows it to operate from input voltages as low as 30mV, regardless of polarity. In this circuit, the LTC3109 provides both a 3.3V output and charges a Li-Ion battery backup in conjunction with the LTC4070 nanopower battery charger.