Area Constrained Multi-Source Power Management for Thermoelectric Energy Harvesting

This paper presents a power management unit for a multi-source single-load system for thermoelectric energy harvesting. The system uses a conventional two-converter architecture and a time multiplexed hysteretic control scheme. The output voltage of four µTEGs with an open circuit voltage from 3 V to 5 V and an internal resistance of 2 kΩ to 8 kΩ are controlled into their respective maximum power point at a maximum measured tracking loss of 2.88 %. Tight system area design constraints require a high degree of integration and the use of a switched capacitor converter as well as an integrated low-dropout regulator. The system achieves a peak end-to-end efficiency of 37.7 % at the maximum input power of 4.44 mW. (Keywords: low power, power management, µTEG, micro energy harvesting)