A Study of the Efficiency of an LTC3108-based Circuit for Thermal Energy Harvesting

The harvest of thermal energy using thermoelectric generators (TEG) to power electronic circuits is getting a lot of research and industry attention due to the possibility of obtaining thermal differences in different day-to-day environments. However, the harvest of thermal energy presents some challenges such as the low level and the high variation of the generated voltage. In this scenario, a solution is the use of power management circuits and DC-DC converters. A widely used integrated circuit is the LTC3108, produced by Linear Technology, which allows harvest voltage levels about 20 mV. An Armstrong-type oscillator is interconnected to the LTC3108 input that is required for proper operation of the LTC3108 step-up process. After this, the LTC3108 performs voltage regulation and energy management to the load. This work describes a simulation-based study of the energy efficiency of the LTC3108 integrated circuit where the input block, formed by the Armstrong type oscillator, has a low efficiency that affects the performance of the whole circuit.