General purpose Power Management Unit Chip for multiple energy harvesting sources

In RTI2018-097088-B we developed 1 mm2 solar cell and a Power Management Unit (PMU) on the same substrate to rise up the harvested voltage above 1.1 V to power wearable or implantable devices. The on-chip solar cell and the PMU are fabricated in standard 0.18 μm CMOS technology achieving a form factor of 1.575 mm2 . Experimental results show that the PMU is able to start-up from a harvested power of 2.38 nW without any external kick off or control signal and can handle a harvested power up to μW with a continuous and two-dimensional Maximum Power Point Tracking (MPPT) that works in open-loop mode to set the frequency‚ the gain and the capacitor sizes of a charge pump.

The research group was granted with a Proof of Concept project from the call “Acelerador de Transferencia” of the Universidade de Santiago de Compostela to carry on a market research to analyse the most interesting niches in which the energy harvesting technology would have a bigger impact. Thanks to this project, a consultancy company hired to develop such market research, identified several verticals, being transport and logistics along with industry 4.0 and domotics as possible market entries to our product.

Through several interviews with companies that work on the field of energy harvesting systems we have concluded that the most spread solutions are based on discrete components that are combined to harvest some IoT node. The proposed system goes beyond by providing a fully CMOS energy harvester. In words of some of the companies this work is two generation product ahead of the product they are currently selling. Thus, the proposed technology would be a very innovative product in the growing market of IoT.

The technology is currently in a TRL-4 as it has been tested in lab conditions, see demonstrator and the goal of this proof-of-concept project is to extend it to a TRL5-6 developing a precommercial product meeting the power requirements of a broader range of application domains.

The novelty of this work lies in the combination of technology-advanced ultra-low power design techniques with a power management unit which permits the use of several energy sources as well as different regulated output voltages while consuming as little power as possible. This innovative approach will permit to develop a high-end product combining energy efficiency and versatility in the number and types of energy sources used as well as in the load conditions.

This project with reference number PDC2022-133933-C32 has received funding from MCIN/AEI/10.13039/501100011033 and the European Union "NextGeneration EU"/PRTR.