For all these while I've been searching for the most efficient way to harvest micro-energy source from the surrounding environment to power up some lighting or smaller devices particular LEDs. So finally I've got the integrated circuit chip from Linear Technology LTC3108 that claimed capable of powering LED as low as 20 mV input source from element14 at a price of RM32 each. It's a very tiny chip as small as peanut with 16 pins (SSOP16).
I was very excited with the prospect of what it can do since I am thinking it could power up LEDs from micro-power generating source such as Radio Wave, WiFi, Phone Signal, Piezo, Thermo generator (Peltier Module) etc. These source of energy can easily generate 20 mV and in fact probable 100 mV minimum for each. So my ultimate aim is to unify the micro-power source to turn into a feasible usable energy that could provide green constant light that will last for a lifetime.
However that was remain a dream for now since I don't have the rest of the component as recommended by Linear Technology especially the 1:100 SMD transformer / coupled inductor and all the SMD ceramic capacitors. For the time being I've just tested on breadboard using ordinary components such as mini-transformers and normal ceramic through hole capacitors.
The result of the experiment shows the lowest power source it could power up an LED is around 220 mV (unstable). For real stability it the minimum input voltage should be around 300 mV or so. The step up provide it produce without load is around 5 Volt enough to power 1 or 2 LEDs.
Below is the circuit