Characterization of the closed circuit response of an on-chip thin film thermopile

The on-chip, closed circuit response of a thermopile with the Seebeck current as the sensory parameter has been reported in this paper. The thermopile was heated with a resistance temperature detector (RTD) at its hot junction. The temperature at its cold junction was higher than the ambient temperature, and was also found to be slightly but measurably different when the thermopile was operated in an electrically open mode as opposed to a closed mode. A user friendly analytical relation, based on a steady state, heat transfer model, is also provided. This model is used to study the non-linear dependence of the Seebeck current on the length of the thermocouple legs and also to estimate the power transferred from the RTD to the thermopile. The experimental work, backed by the simple model, is aimed at providing some insight in using a closed circuit on-chip thermopile not only as a temperature sensor but also as an electrical power generator.