1 mV-input voltage step-up circuit with 8 μW output power for thermoelectric power generators

A voltage step-up circuit with ultra-low input voltage is desirable for thermoelectric power generation. However, existing circuits with a few mV input voltage can output only a small power of at most 1 μW. In this study, a charge pump and a boost converter were investigated to obtain larger output power from 1 mV open-circuit input voltage. It was found that the load resistance should be matched not only with generator resistance but also with parasitic resistance of the boost circuit, which severely limits the output power. We elucidated by simulation and experiments that an output power more than 8 μW is only possible when total parasitic resistance is suppressed less than 24 mΩ, and in addition, a boost converter is more suitable for device scaling than a charge pump. The results will contribute to the widespread use of thermoelectric power generation by reducing constrains on output voltage. • Achieved voltage step-up from 1 mV input to 0.85 V using a boost converter. • Demonstrated parasitic impedance matching outperforms traditional matching for 1 mV input. • Demonstrated output power above 8 µW from 1 mV input. • Promotes wider application of low-cost, reliable thermoelectric modules.