Conclusion
An integrated solar controller synthesizing both battery charging and LED driving functions for offgrid
lighting system is proposed. The BDC for the integrated solar controller with Sepic and Zeta modes
improves the control flexibility of voltage level matching among solar PV panel, battery, and LED
module. Analysis shows that there is always a monotonic relationship between the operating voltage of
PV panel and duty cycle of power switch regardless of inductor current continuous or discontinuous
modes. Either static or dynamic MPPT efficiency of the integrated solar controller in charging mode is
quite good. The digital hysteresis constant control of the integrated solar controller in driving mode is
proposed and verified by experimental results