IP개요 |
This paper discusses a multi-energy harvesting interface IC by considering two energy sources with very different internal source resistances. An electromagnetic vibration energy generator (EVG) and a thermoelectric energy generator (TEG) are the selected energy sources. Those have chosen internal resistance values of 1.5 kΩ and 50 Ω, respectively; therefore, it is usually quite hard to combine them for energy harvesting. Initially, the internal circuits can be powered by using EVG. Then, the two energy sources, EVG and TEG, are switched alternatively for transferring the source power to the output. Especially, there are two kinds of maximum power point tracking (MPPT) algorithms in order to obtain the maximum energies as well as select the right times for enabling both sources. Furthermore, the first and second MPPT algorithms have been realized by using pulse frequency modulation (PFM) and pulse width modulation (PWM). The multi-harvester has been fabricated in a 0.18 μm process and it achieves the maximum end-to-end efficiency of 82 %. |