SBIR Phase I: Micro-Solar Powered Battery Charger Circuit

This Small Business Innovation Research (SBIR) Phase I project will research and develop an efficient, integrated single-chip solar powered charge control circuit charging lithium ion (Li-Ion) and nickel metal hydride (NiMH) batteries from micro-solar panels for remote sensor and portable electronic applications. To achieve this goal, our investigation will focus on the following areas: 1) Research and development of an efficient power control algorithm and boost circuit optimized for applications using micro-solar cells, 2) Research and development of programmable embedded control circuits required to automatically control proper charging of Li-Ion and NiMH batteries. The intellectual merit of the proposed activity is to provide efficient, low cost solar energy harvesting solutions for autonomous sensor and mobile consumer electronic products. At the end of this project, an integrated, single chip maximum power point tracking (MPPT) circuit with integrated voltage boost and programmable battery charger circuitry will be demonstrated. The novel automatic MPPT algorithm enables a single solution for 1 to 8 cell panels without a change in circuit board parameters and eliminates the need for external microcontrollers. The integrated boost/MPPT features do not exist on the market today. The broader impact/commercial potential of this project is very large because of the scalable nature of this technology. Scalable energy harvesting system blocks have application to solar charging for portable products, autonomous wireless sensors for real time system control, and larger rooftop solar harvesting for residential and industrial applications. This wide application space represents a significant opportunity to enable harvested renewable energy and reduce dependency on non-renewable energy sources. From a commercial perspective, all of these applications are anticipated growth markets over the next decade. Growth in cell phone use in developing regions like Africa, India, and China offers a large opportunity for solar charging. In addition, the recent earthquake in Japan has highlighted the need for solar charging for cell phones and flashlights when the power grid is vulnerable to natural disasters. Efficiency improvements in new wireless sensors systems and residential/industrial solar power systems will drive new demand and provide reduced costs of adoption for consumers. The results of this research project will increase solar energy harvesting effectiveness for small and large systems thereby providing consumers with new choices for energy savings and new freedoms for grid-independent power.