Driver options for MC-E

[bbgobie]

If wired in Parallel the 2.8-3A one on Kai should work.

Theres a few like the maxFlex that would work if in series. But is there any lower cost ones available?

Looking to drive in series at 700mA.
Battery 7.4V -2200mAh so would need a boost.

2-5 modes would be nice (High-low) preferred.

Don't want to spend in the $30 or even $20 range as the maxFlex has been proven reliable. But was hoping to be around the $5-10 range to test out.

 

[mudman cj]

I think you will like this option.

 

[bbgobie]

Thx
It looks interesting, but I'm not sure I get how it would work at first glance.
I think I"ll have to really sit down and think that circuit out in my head this weekend.

 

[ahorton]

Not that it's anything new, but I'm doing it something like this:

Orange lines are my own PCB (note that I got the nice transparent 7135s).

I have made the left version but will try the right sometime soon. I really want to run at 7.4V since I already have a handful of 2 cell Li Ion and LiPo packs. The thing that deters me is running the 7135s at 4.8V with fresh cells (my MCE's dies have Vf of 3.5-3.6 at 700mA). If they don't get too warm, then I'll probably go with the the right version.

I'm curious to see which is more efficient overall. The left keeps the the voltage closer but the right will stay in regulation longer. The right will run brighter for longer, but it is burning off more power when the cells are fresh.

Edit: The right one is made and works well. Holds the LEDs at higher Vf for much longer so I think it is the more efficient. I think I'll stick with this option.

 

[gillestugan]

I would recommend using a 4x7135 driving the leds 2x2. You place two paralell dies in parallel in front (series with) the driver and 2 driven by the driver. you can use a multiple mode driver and it's cheap and effective. If you want higher output, just add more 7135s to the board.

Im planning to use a 7135 based driver for MC-e driven at 14.8V in this setup.
http://www.candlepowerforums.com/vb/showthread.php?p=2560909#post2560909
I've used this setup with XR-Es for a long time and it works great. Have used this driver http://www.dealextreme.com/details.dx/sku.7612


Alternatively use direct drive at 11.1V and be able to switch between 3 and 4 dies i series. Will make two modes: very high and very low. Low about 25mA wich is good for reading. Unfortunately high would have a really ugly hotspot with only 3 of four dies running.