Thermoelectric energy harvesting systems in accordance with embodiments of the invention enable energy harvesting. One embodiment includes a thermoelectric energy harvesting (TEH) system comprising a TEH comprising a thin-film array-based TEH source start-up mode circuitry comprising: an upper branch comprising: a mode switch configured to allow selection of the upper branch an inductive-load ring oscillator (ILRO) a charge pump configured to receive an input from the ILRO and output current, where output current is utilized to charge an upper branch capacitor a lower branch comprising: an inductor an active diode configured to transfer energy stored in the inductor to an output capacitor maximum-power-point tracking (MPPT) mode circuitry, where the MPPT loop comprises: a mode control unit a gate controller a clock generator configured to generate at least one control signal an analog-domain MPPT unit configured to receive the at least one generated control signal.
