done.

Secondly, it is studied about the LED's electrical characteristics, power selection,combination method and so on, focusing on the optimizing design of LED hardware driver circuit. Finally, on the basis of PAM2842 drive chip,LED drive circuit is designed to achieve their applications. Input voltage is selected as 24V by PAM2842, to drive street light which is composed of ten white LEDs with 3W by a series. Input constant current is 700mA to ensure the stability of the lights work,and there is overvoltage protection circuit, making voltage limited to 37.2V. If a single LED is short circuit, it can pretect all the other LED against burning because of the high voltage,to ensure the safe usage of street lamps. Therefore,based on the above research, the system of solar LED street lighting has been designed.

Finally,the comparisons of laying of street lamps and cost in Wanbailin District of Taiyuan City are analyzed as an example.

Keywords: photovoltatic electricity,Solar Controller,Battery,White LED light source,LED drive circuit,LED Street Lighting