I have been researching a way to use ultra capacitors too their full potential. I could use some idea of a boost circuit that could help fully deplete a ultra capacitor? The ultra capacitors intended purpose is to be used to power a 5 watt led at 700ma. So I need a boost circuit that will work with a constant current led driver. Is there any possible way to use voltages lower than the led forward voltage to power the led with some sort of led driver?

I have not built a led driver yet. I have only tested the led with a resistor.

 

Sure, a switching converter can increase voltage to drive the LEDs. There are many switching up-converter topologies: boost, buck-boost, SEPIC, Ćuk.

Let's ask our good friend Google for some help.

 

Oh yes, and definitely check out the Joule Thief.