Alternatives and Limitations of Off-the-Shelf Power Management Circuits for Low-Power Thermoelectric Generators

In the field of power management circuits (PMC) for low-power thermoelectric generators (TEG) intended for autonomous sensors, this article experimentally evaluates the alternatives commercially available. Considering their limitations in terms of minimum input voltage and power efficiency, this article also proposes and experimentally characterizes a circuit topology that combines and interconnects two different PMC alternatives so as to achieve the benefits of both. Thanks to this interconnection, the resulting circuit is able to start operating from a low input voltage (i.e., 40 mV of TEG open-circuit voltage), which is really attractive for TEGs under low thermal gradients, with a satisfactory power efficiency (i.e., up to 78 %).