A Batteryless Thermoelectric Energy-Harvesting Interface Circuit with 35mV Startup Voltage

摘要

Energy harvesting is an emerging technology with applications to handheld, portable and implantable electronics. Harvesting ambient heat energy using thermoelectric generators (TEG's) [1] is a convenient means to supply power to body-worn electronics and industrial sensors. Using TEG's for body-wearable applications limits the output voltage to 50mV for temperature differences of 1-2K usually found between the body and ambience. Several existing systems [2, 3] use a battery or an initial high voltage energy input to kick-start operation of the system from this low voltage. Further, changing external conditions cause the voltage and power generated by the TEG to vary, necessitating efficient control circuits that can adapt and extract the maximum possible power out of these systems. In this paper, a battery-less thermoelectric energy harvesting interface circuit which uses a mechanically assisted startup circuit to operate from 35mV input is presented. An efficient control circuit that performs maximal end-to-end transfer of the extracted energy to a storage capacitor and regulates the output voltage at 1.8V is demonstrated.