The controller has two tasks

1. Charging the Battery:

Isolate the Solar Panel and Battery when the battery is fully charged and Isolate the load from the Battery when the battery voltage is low.

2. Driving the LED:

Capable to drive the selected LED ( ability to handle the required voltage and current ) i.e Boost the battery voltage ( 1.2V ) to LED operating voltage (3.2V) or higher

Here we will use a cheap QX5252F IC as a controller.

The main features are:

1.Suitable for a single AA NiMh/NiCd battery

2.Operating Voltage: 0.9V-1.5V

3.Output current: 3mA-300mA ( Our requirement is 93.7mA )

4.Integrated Schottky Diode

5.High Efficiency up to 84>#/p###

6.Low quiescent current: 17uA ( When the circuit is not working / standby )

7.Only an external inductor is required for making the Circuit