An adaptive load-line tuning IC for photovoltaic module integrated mobile device with 470µs transient time, over 99% steady-state accuracy and 94% power conversion efficiency

Many modern mobile devices have a touchscreen and are powered by a rechargeable battery. To extend battery usage time before recharge, harvesting energy from ambient light provides an elegant solution if the photovoltaic (PV) modules can be integrated with mobile devices [1]. However, mobile devices are frequently finger operated and/or in motion, so light-harvesting should consider fast-changing shading and partial shading problems. Previous IC works [2-4] have reported on the implementation of maximum power point tracking (MPPT) for light-harvesting, none of them have concurrently addressed these two problems. Although one of these works [3] considered the mobile device issue, it targets high MPPT steady-state accuracy without considering fast-changing shading problem. Hence, there is still room for improvement with respect to short MPPT transient time to harvest more energy for extending battery usage time.

[1]  Alex Q. Huang,et al.  A high efficiency DC MIC for PV energy harvest in FREEDM systems , 2011, 2011 Twenty-Sixth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[2]  M. Vitelli,et al.  Optimization of perturb and observe maximum power point tracking method , 2005, IEEE Transactions on Power Electronics.

[3]  Chris Van Hoof,et al.  5μW-to-10mW input power range inductive boost converter for indoor photovoltaic energy harvesting with integrated maximum power point tracking algorithm , 2010, 2011 IEEE International Solid-State Circuits Conference.

[4]  Anantha Chandrakasan,et al.  A 330nA energy-harvesting charger with battery management for solar and thermoelectric energy harvesting , 2012, 2012 IEEE International Solid-State Circuits Conference.

[5]  Horst Zimmermann,et al.  A maximum power-point tracker without digital signal processing in 0.35μm CMOS for automotive applications , 2012, 2012 IEEE International Solid-State Circuits Conference.