22mm 16x 7135 driver for F13 flashlights - [released]

ah…forgot about that

And I guess if you get a good off time build you probably won’t be reflashing that often huh?

Yeah, that’s a minor problem… :wink:


This version has:

  • 0.5mm vias added to the GND ring
  • thinner Vcc trace routed between pins on MCU
  • 1.1mm vias for LED- and LED+ to accommodate ~20AWG stranded wire.
  • copper pours slightly larger than 1x1mm for LED- and LED+

I haven’t gotten things 100% worked out with where I’m removing the solder mask for LED- and LED+.



First set is on the May 04 panel!

tStop on minus pad

need - and + on tDocu

And I usually make the identifiers .6~.8 but that’s just me (yeah…nitpicky I know)

And need a BLF on it somewhere :wink:

I did mention that in post #10. There’s plenty of copper there to solder to. I’ll probably leave both pads covered in the next version and remove the mask from at least part of the two big vias. If someone wants to solder to the small 1x1mm surface area they just need to scrape.

Identifiers? The GND vias are 0.5mm because that’s what fits.

The tDocu letters R1, U1, the white letters on the silk screen (identifiers ???)

Still a pretty darn cool design

Oh, gotcha. I just ignore that stuff until the rest is sorted out.

Is R1 a resistor or diode?

Depends on whether D1 is populated with a Zener diode or not.

I was confused why there is a zener diode for a single cell flashlight driver. I'm guessing you're designing in options for use in other lights later on?

It looks good.

Well, really just for flexibility. Mainly as you say - in case someone wants to use it in a different light. Also though, someone might choose to run the F13 on a pair of 18350. Or if some battery manufacturer ever made a good 26350 :drool:

Thanks, I couldn’t reconcile the print and the pictogram.

Don’t tease me bro.


What did I change? I don’t know. I spent too much time tweaking stuff tonight.

  • I moved the offtime cap away from the MCU. In order to move it as far as reasonably possible I had to reroute the PWM trace. The PWM trace did not have another clear path to go out of - there isn’t enough space next to the voltage monitoring trace as it is now. So I ended up having to do some funny business there in the upper left where Vcc goes onto the bottom of the PCB to get to the MCU. I seriously doubt that any clip will be able to grab the MCU, but this should make messing with the MCU easier.
  • I reduced the annular rings on the vias to improve clearances next to the big 1.1mm LED+/- vias. I re-covered both solder pours with mask and uncovered the +/- vias.
  • I labeled everything I wanted to - I do realize that the zener only has a zener symbol and the offtime cap is unmarked.
  • I marked two sets of 7135’s: “A” and “B”. You must place a 7135 or jumper to GND with at least one location from each set. Each set has 4x 7135’s in it, two on top and two on bottom. It should be really easy to make sure at least one from each set is populated.

Just for fun, here are the drills:

I realized that there was no reason for the exposed copper GND ring on the bottom of the board in this application, and it’s actually a pain because it prevents you from easily aligning the 7135’s. So I put the mask back over that and removed the mask from the vias because I think that looks cool and why would I need a better reason than that :wink: I also realized that I do not have a polarity marking for D1. Oops. Hopefully that gets fixed in a future revision. Maybe I’ll feed the voltage divider directly from BAT+ in a future revision too.

My first set is on the June 06 panel :frowning: Can’t wait!

Very nice!

The drills looks like the starry sky :slight_smile:

Those thru hole wire positions are nice…huge thick wires can be used…excellent

What is the 7135-A and B for…not populating all the 7135 positions for zener builds??

Thanks! Starry sky was my first thought as well, I was paying attention to something else and it took me off guard when I scrolled past the drills on Oshpark.

All the 7135’s on the bottom are grounded…

I’m a bit confused…the center pin on the 7135 has a solid connection all the way thru underneath to the tab on the back…so the bottom side with the spring, when you solder them down they are all automatically grounded

And I see the thru holes from the bottom go to the top sides, so they too would be grounded…correct?

And on the top side, you could put a simple trace from the back pad to the ground ring under the solder stop

Ah, but if they ain’t there in those A and B position…no under the chip ground path…NOW I see it…DUH! (smack head, coulda had a V8 moment :stuck_out_tongue: )

Not everybody wants 16*7135 inside these little flashlights! I imagine that this PCB will generally be used with something in the range of 4*7135 to 12*7135.

There are two portions of the circuit which required ground paths and do not have a direct connection to the main GND ring.

  1. C1 is the Vcc input/smoothing/whatever cap. It requires a GND connection but cannot reach the GND ring. Placing a 7135 on any placement marked 7135-A connects this ground.
  2. MCU & zener ground connection. Same deal. They can’t reach GND. Placing a 7135 on any placement marked 7135-B connects this ground.

C1 is the easiest example to look at. It obviously has no ground connection unless one of the 7135-A placements is populated. We are using the “solid connection” you mentioned as a zero-ohm jumper to get past the blocking trace!

Since I used a complete ring on both sides there is actually space to break the PWM and LED+ rings and allow a path to GND. Maybe I’ll do that. Personally I like complete rings and I see no scenario where at least one position on both A and B wouldn’t get populated.