[2023] Inductor-less Highly Efficient Solar Energy Harvesting for Self-powered Wearables

Energy harvesting has become an extended solution for low maintenance, small size and battery-less systems, such as implantable devices, wearable devices and smart wireless sensor systems. When these devices are implemented/used in outdoor environments, sunlight can provide a considerable amount of energy even with a small solar cell. For indoor environments, the illuminations from lamps and reflected sunlight are also good energy sources to harvest.

Recent years, there has been many research projects and commercial products on solar energy harvesting (EH) systems. Since these EH systems are used to power miniature sensors and devices, the solar cells are typically very small (a few mm^2 to a few cm^2). These small solar cells usually generate low power levels with low output voltage, which introduce several challenges on designing the power extraction circuits [1][2][3]. In addition, the fast varying illumination levels in the environment require fast maximum power point tracking (MPPT) techniques to maintain the system at the optimal efficiency. Furthermore, the unavoidable inductor in the system for power conversion significantly increases the system size, which is counter to miniaturization of IoT devices.

In this project, we are going to design a highly efficient power extraction integrated circuit for solar micro-energy harvesting to power miniature IoT and wearable devices. The design system will enable stable cold-start under low illumination, fast MPPT performance and high end-to-end energy extraction efficiency.

[1] Z. Chen, M. Law, P. Mak, and R. P. Martins, "A Single-Chip Solar Energy Harvesting IC Using Integrated Photodiodes for Biomedical Implant Applications," IEEE Transactions on Biomedical Circuits and Systems, vol. 11, no. 1, pp. 44-53, 2017.

[2] P. Huang and T. Kuo, "A Reconfigurable and Extendable Single-Inductor Single-Path Three-Switch Converter for Indoor Photovoltaic Energy Harvesting," IEEE Journal of Solid-State Circuits, vol. 55, no. 7, pp. 1998-2008, 2020.

[3] E. Ferro, V. M. Brea, P. López, and D. Cabello, "Micro-Energy Harvesting System Including a PMU and a Solar Cell on the Same Substrate With Cold Startup From 2.38 nW and Input Power Range up to 10 uW Using Continuous MPPT," IEEE Transactions on Power Electronics, vol. 34, no. 6, pp. 5105-5116, 2019.

Assignment

1. Literature review of solar energy harvesting topologies and associated power management circuits.
2. Design of a highly efficient CMOS circuit for the proposed solar energy harvesting system. Tape-out is possible depending on the design and available time.

Requirements

You should be familiar with analog IC design and Cadence environment. If you are interested, please send your CV, BSc transcripts and MSc grades (obtained to date) to Sijun Du at email: Sijun.Du@tudelft.nl

Contact

Last modified: 2022-12-29