I had problems with SRK drivers based on 7135’s. It works only lower modes and full. Depending on input voltage, it will just turn off when trying to use mid to almost high modes (like 100-254). I found that if i move that C1 to before D1 it works much better. And i understood that it should be like that because otherwise MCU could get voltage spikes and that’s the reason for these higher modes not to work.
Now i saw that DEL’s latest 7135 driver has resistor before MCU Vin, so this is the correct way to fix this issue? Maybe with this way i could make these SRK 7135’s drivers to work correctly?
What MCU are you using? For the 25/45/85, they can be unstable on the old-style OSHPark you linked. This is why all our new board designs have the extra resistors: R3, R4, and R5 (R5 sometimes is R6). Out of those, the most important one is the R5/R6 4.7 ohm that must precede the D1 diode. I've modded some standard 13A drivers by cut/jumper, and tombstone in a 4.7 ohm resistor.
Hhmm, I dunno then. Sounds like it's PWM related. Have you tried an alternate firmware? Which firmware are you using? Might be something like a bad 7135 or solder joint, but if it happens on multiple boards, probably not. Could be issues maybe with FAST mode PWM's, or just the higher clock rates of PWM. This board uses a lot of 7135's, so many borderline spike/noise issues are amplified to a point of a problem. That typical D1/C1/R1/R2 circuit design barely gets by with 13A's. In fact I believe the spikes are out of spec with the 13A, just that the 13A tolerates them better than the 25/45/85's.
I think i have tried only this STAR_Momentary firmware:
7135’s have been those from Fasttech 100pcs packs, so far these “Raptor Claws”.
I have tried both FAST and PHASE PWM, made no difference. Clock rate i have not touched, maybe need to try that too.
Also i’m not 100% sure if it behaves like this with batteries, i don’t remember whether i tried or not. I test these with lab power (Manson HCS-3302) before putting in host. I did read for a long time ago about this C1 misplacing and i just moved it and it seems to work. But now that i saw this DEL’s way to do this, i started to think if i’m doing something wrong.
+1 what Tom said about the small resistor. Replace D1 with a series combination of a 2 to 10 ohm resistor and the original D1, then you should be good to go.
I do have a 16x 7135 driver board on OSH, shared and ordered, but it only shipped yesterday. It should be good though.
Ok, thank you very much for confirmation, i’ll try that next time.
For FET driver, isn’t it “direct drive” with PWM value of 255? I think that could be only option for ~3-4pcs of XML2 in SRK, for more leds that will make so much current for such small host and with modern batteries that could give so much current still keeping voltage high. With these 7135’s i can control current much easier. Or am i missing something here?
Strange you're having issues with that driver. Yes, it is the "old configuration" with the capacitor after the diode, but I have built and sold hundreds of these without experiencing that issue. Tom has used them as well, even souped up if I recall.
Well i have to try next time with batteries before making any changes to make sure it is not failing because of my lab power.
But after moving C1 before D1, it has been working nice. Very good board thanks!
I’m learning how to use Eagle now and i was thinking to try draw SRK board with 3-4 7135’s groups so i could use without PWM, or maybe one 7135 with PWM, for best efficiency. Is there really sense, maybe not. After that there is ofcourse problem with firmware, don’t know if someone has done that already.
I don’t know how i didn’t saw that there was really three channels used in that code and pcb, but yes, there really is. Have to say this looks really awesome, Texas_Ace has done really huge work for this driver!
4 parallel 18650 battery plates. I’ve searched and cant find anything. does anyone know if they exist or even a battery carrier the ends can be robbed from? This is for the Ol comp light build.
OSHPARK says there must be a 15 mil clearing between traces and outline. Shouldn’t this also affect the ground ring on our flashlight drivers? I have checked a couple of board designs from forum members and have NOT seen this clearance anywhere. Isn’t oshpark that strikt with its design rules, or did they correct the gerbers or what else?
It is hit and miss, sometimes they cut the copper back from the edge of the ground ring and sometimes not. I always have it extend to the edge and if they cut it back, so be it.
On driver that are really tight you can oversize the pcb and sand it back to make sure there is copper to the edge.
