Using LED Drivers to Lower System Voltage for Low Cost Solar Lamp Project

I'm looking into LED drivers as a potential method of reducing required system voltage, thereby dropping the third NiMH battery I was planning on and also allowing the usage of a lower voltage/larger current solar cell. Right now it looks like a win/win, but I don't have any experience with these.

I guess I'm looking for both general thoughts on LED drivers, any experience or tips, as well as feedback on the rationale of using it in my project.

Specifically this would be part of the low cost solar lamp project I've discussed as a project.

Josh,

Your projects sounds interesting. An LED driver is a good choice for your application so you can boost your output voltage without requiring more battery cells.

There's plenty of LED driver out there. Let us know what parts you end up choosing. I think Digi-Key has a sort by price option now in their search results.

Joe,

It looks like I'll probably go with the driver founds here: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=ZXSC380FHCT-ND

It's not the cheapest, however, it's basically the cheapest that goes down to ~.8-.9V, which I figure is an easy way to extend battery life. It also requires an external inductor, which I'm not to happy about, since I'm trying to keep component part to a minimum. But I think this would still be a significant improvement over using three battery cells to power the project.

And I don't know why it took Digi-key so long to put a sort by price feature, but it sure is nice...

Joe,

So there seems to be one relatively large issue with the part I was looking at. At the voltage ranges I'm looking at, the maximum output current is pretty minimal. I thought an average of 10mA would be sufficient if not ideal. But the LEDs are quite dim at 1.2V input and basically useless below that.

This one: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=ZXLD383ET5CT-ND is setup differently internally and a smaller external inductance increases the current to the LEDs. It is interesting to note the extreme difference between the average and peak current when using these drivers.

I'll keep looking...