Step-Up DC-DC Converter Supplied by a Thermoelectric Generator for IoT Applications

Abstract

This research work aims to design and prototype a DC-DC converter to step up the low voltage of a small, low-power thermoelectric generator (TEG). The system is based on an inductive boost converter and attains a regulated output voltage of 1.2 V. The design’s optimisation was based on simulation and experimental validation and it was implemented with only ten low-cost commercial off-the-shelf (COTS) components. To reduce complexity, the low-side switch MOSFET of the boost converter is directly driven by an LC oscillator, switching at 1.25 MHz. For loads above 20 kΩ, the converter ensures voltages higher than 1.2 V, supplied by the TEG voltage of 0.5 V, while registering identical efficiency values to those of more complex and expensive CMOS-integrated solutions. These designed features suggest applications in remote IoT nodes and portable devices, delivering sufficient power to backup the supply of corresponding sensing and communication low-power circuits, reducing the necessity of battery replacements or increasing their lifetime.