I want to build a 90% efficient microcontroller based LED driver circuit with current range from 25mAmps to 35mAmps with the source voltage of 7.4 volts. How can I make it using my Arduino board.
1.) 24 to 32 LED's.
2.) LED load is of 3 to 3.2 volt.
3.) 7.4 is the source voltage which is charging a 3.7 volt lithium ion battery i.e LED's wil be powered by the lithium
ion battery.
Please help.
Thanks for your concern SunnySkyguy.
I have a 7.4 volt solar panel from which i will charge the 3.7 volt Lithium Ion battery. This lithium ion battery has to drive the LED's(32 LED). Please tell me a suitable LED driver which matches my specifications and the corresponding circuit diagram. Microcontroller (arduino) is for other side tasks such as high HCO(high cut off) and LCO(low cut off), battery voltage sensing etc.
LiPos have the tendency to explode when charged incorrectly.
1st consider efficiency of 32Parallel LEDs with Lipo charged from **broken link removed** or equivalent
Then consider LDO with series R for each LED. Efficiency is approx 3.2V/3.7 = 86% for LDO
Charger efficiency using 7.4 to charge 3.7V LiPo @ 4.2V is much less. so overall efficiency of 90% is not possible with linear charger. Actually the problem is choice of PVC voltage and battery voltage is too low to make high efficiency.