This article introduces an ultralow voltage energy harvesting system that uses a thermoelectric generator to power wireless sensors without batteries or wires. The system is widely used in areas such as building automation, wireless/automated metering, and predictive maintenance.
The October 2010 issue of the LT Journal of Analog Innovation from Linear Technology features articles on various electronic design topics. Key highlights include new 4- and 6-supply monitors with ±1.5% accuracy for rails down to 1.2V, a compact IC producing multiple power rails from a single Li-ion cell, and passive mixers that increase gain in downconverter applications.
A major focus is the cover story on ultralow voltage energy harvesting using thermoelectric generators (TEGs) to create battery-free wireless sensors. The article details how the LTC3108 acts as a missing link by providing power management for TEGs with input voltages as low as 20mV, enabling autonomous systems in industrial and consumer applications.
The converter can start up with inputs as low as 20mV.
The most common sources available for harvesting are vibration (or motion), light and heat.
They generally produce very little average output power, usually in the range of 10µW to 10mW.