A Symmetric Boost Converter With 6 mV Input Voltage and 66% Peak Efficiency for Thermoelectric Energy Harvesting

This article presents the design, simulation, and experimental validation of an ultralow input voltage symmetric boost converter tailored for thermoelectric energy harvesting in energy‐autonomous wireless sensor nodes. The proposed DC–DC architecture combines a Meissner oscillator with a forward converter stage, extending cold‐start capability and sustaining high efficiency across a broad input range. The circuit operates without any auxiliary supply and is fully powered from its input voltage. A custom microtransformer was developed and optimized through PSpice simulations, ensuring reliable operation under the constrained power conditions typical of thermoelectric generators. Within the practical input range of 20–50 mV, the converter delivers 1.33 and 7.18 mW output power, achieving a peak efficiency of 66.9% at 20 mV input with 5.5 V output. Efficiency remains consistently above 63.9% across the tested input range. Cold‐start operation is demonstrated from 18 mV, delivering 17.95 µW, while stable post‐cold‐start operation is sustained down to 6 mV with a regulated 2.12 V output. These results establish the converter as a viable solution for harvesting energy from the minute thermal gradients available in real‐world environments, thereby enabling long‐term, maintenance‐free wireless sensor operation.