Boost Converter Powered by Thermoelectric Generator to Harvest Low Temperature Waste Heat

This article discusses a self-starting low voltage low input impedance dc-dc boost converter that powers electronic devices by gathering body heat using a thermoelectric generator (TEG). TEGs with low input impedance can produce moderate power but the output voltage (a few mV) is low. Such TEG operating at low temperatures needs a boost converter to directly power any electronic devices. In this study, a common drain amplifier with transformer feedback is employed to demonstrate a frequency-independent high gain. Its low voltage self-starting capability enables the boost converter to start at the lowest input voltage. The flyback converter as a boost converter offers a low input impedance which makes the converter circuit suitable for TEG applications. The simple supervisory IC based logic circuit connects or disconnects the load according to the requirement. The boost converter consumes 41 μ W power to self-starts at 16mV. It achieves $72 %$ maximum efficiency at an input voltage of 59mV. The output voltage of 2.72 ~V and power of 4.47 ~mW at maximum efficiency are sufficient for low-power electrical gadgets.