Another 7135 Driver Wiring Question

[Roland Gama]

It will work if you knock out the chip/ resistors as in one of my pics in this same thread.

 

[kramer5150]

Is there any limit to the number of these things you can parallel stack? Is it possible to stack enough of them and drive an MC-E?

thanks

 

[Roland Gama]

https://www.candlepowerforums.com/threads/212835#post2698569

 

[dnlwthrn]

Found a schematic of a AMC7135 on the web and made this diagram.
Looks like the schematic is not exactly how the 7135s are used on the board in the picture.
I think just looking at the picture that the ATMEL chip is driving the 7135's???
A real schematic of this board from the manufacturer would be the ticket.

I don't have one of the boards in front of me, they are on backorder and I am still waiting for mine.

I manufacture electrical items and I always need schematics and technical info on chips, etc. I can't believe DX doesn't have a spec sheet/schematic info tab on all these sorts of devices. Drives me nuts when you are trying to design something and need the spec's of a device.

Hope everything is correct on my diagram. I'll know for sure when I get my hands on a board. If anyone sees a problem, I'll fix or add something to the diagram.

I just got one of the boards from DX today, and while it looks to be similar, the layout is different. Just trying to figure out the wiring... EL34, do you have any tips on what I can check to verify things? I have a DMM and really fine tipped probes, just not enough background with these things to know what should go where.

Here's a photo:

The two 7135s on top are L7135 0704, while the one on the right is a 7135 35k.

 

[Justin Case]

Use your DMM in continuity mode (where the DMM beeps or buzzes if there is continuity, and no sound for no continuity). You can trace what terminals are connected to what by touching the DMM probes between all of the various connections. To assist in determining what is wired to what, you can also put the driver board on the glass window of a flashlight and backlight the board. The traces should show up dark, and that should also help you trace the connections.

 

[dnlwthrn]

Cool. The backlighting thing really helps, never tried that before. It appears that (and I just tested it and it works) the + connection for the LED goes to the pad just to the right of the ATMEL chip, and the - LED goes to the pad on the top left (that has a - next to it).

Now to rewire my light for this board... Gotta drop the Vf to an acceptable range (running multiple red Crees in series right now, ~6.6Vf).

 

[dnlwthrn]

Ok, new problem... I can't seem to make this work with red LEDs. Running one emitter alone, I have a Vf of ~2.2. The board (for obvious reasons) won't power them when wired in series, and when they're in parallel, it just turns on dim and flashes at a rate of ~.5hz (low power warning?).

The only option I haven't tried yet is to do a 1P2S setup and try that, but I'm wondering if there's a way to mod the board to work with a lower Vf...

 

[Tommu]

...
Anyways I want to mod 2 of them up to ~1.3A output, by adding a 4th 7135 driver, per the pic below. by transplanting parts from the donor board....

Kramer,
I moved a 7135 from one board to another. like your diagram shows
(empty spot on my board is in the lower right in my pic)
It works. 1.37A output.

Isn't that Atmel overdriven? Could it survive for long time?

 

[Packhorse]

The Amtel chip does not see any current for the LED's. It simply drives the 7135 chips. It should drive 10 or more 7135's with ease. Maybe 20 or 50. Who knows.