7135 driver chips

Flashlight Modding and DIY Parts
23

great, thank you, I appreciate everyones help. very informative. so if I were to have a very good battery(feel free to make suggestions) and was using a convoy m1 host with an xp-l HI v2 what would 50% be and how many 7135’s total would I need to handle that?

24

and is the double down driver capable of this or are there any possible options from somewhere like mtn-electronics?

25

You could get about 5amps, so half is 2.5, about 6-7 chips.

However, your eyes don’t see light increases linearly. If I have 4 modes including moon, 1/3 of max is a better medium. Each 7135 is 0.38amps, so about 4 chips

26

For more info on how this would actually work, talk to Mike C. He has already designed one that uses multiple 7135’s in groups so that most steps require no PWM at all, with a FET used only for turbo. :party:

27

is there a link to where he has them listed some discussion about it? thank you again,

28

I’m clearly a noob so please educate me if I’m wrong. Isn’t what you are doing essentially the same as what has been done with the BLF A6 group buy? As I understand the driver over there it is a combo single 7135 and an FET (from the title of the thread: BLF A6 FET+7135 Light). An ATTiny running ToyKeepers custom (but open source and published) firmware controls them.
BLF A6 GB thread

I totally get it if you want to roll your own, I’m just trying to understand how (or if) what you want to do is different.

Lazy-R-us

29

yes I was aware of that driver. that was what prompted me to start asking these questions. but what I would like is not just the lowest mode but all of the modes except high to be reg by 7135’s so that I can get a high high with the fet and regulation and dependable output and runtimes on the other modes from the 7135’s.

30

Yeah, he mentioned it in a couple places, but it’s hard to track down, since it is in other people’s threads. AFAIK, he hasn’t started a thread of his own about it. I did find in the Attiny25/45/85 thread, he had this to say in post #178:

In post #185 of the same thread, he said this:

31

Edit: Removed images, new version in the pipeline…

hmmm… interesting. half of it is over my head the other half i get. I wonder how much such a driver would cost? I was going to see if Richard could throw something together over at mtnelectronics
he already has the fet / 7135 driver combo like was said above i wonder how hard it would be to add a few 7135’s to that driver?

32

You could stack 3 7135’s on the single 7135 footprint for up to 1A regulated and then high and turbo through the FET.

33

Yes you can and I’ve done it. It works great (as long as you are reasonably good at stacking).

34

That’s a neat way to save space. Is there a custom heatsink for that?

35

36

I guess not :slight_smile:

37

Touché.

38

Driver pockets generally have enough headroom to stack several chips so depending on the light you might be able to install more. When I do a tall stack I glue them together first then braid fine wire around the pins to wick the solder and carry output current and ground.

39

Wow… That would make things much easier. I’m going to start doing that now

40

That does look nice.

41

Yep, I guess I oughta try that myself! I have such a hard time even stacking one on top of another!

42

My plan is to stack them like that before I even reflow the first one