Thats really nice work DEL.
So without the Fet you have to modify the firmware so the driver will work?
Thanks MRsDNF! It is still a 2-channel driver, so Narsil works out-of-the-box. But to get a smooth ramp the ramp values need to be recalculated to suit the 2.1 A range, rather than the expected 10+ amp range (I used the latest NarsilM, configured by default for the Q8). Otherwise there is a noticeable pause/plateau around where the higher-power channel kicks in.
The K2 has two indicator LEDs behind the button, I still need to add firmware support for the second (red) LED.
Thanks for the explanation DEL. Tom will tell you and I agree with him that I’m totally clueless on how this all works. :person_facepalming:
Just ordered the K2 board sets - nice DEL! Over the weekend I actually was able to crack open the thread lock on the K2 tailcaps - all 3 I have 
. Also got the bezels off of a NiteCore MH20 and Astrolux S41 open.
DEL - finally assembled an HQ BLF SRK v3.4 driver with your C3 and C4 mods. Goin in a triple XHP70.2 Haikelite MT03. Hopefully will start testing soon.
Edit/Results: it worked for a little while, while ON though, noticed something like a flicker. From that point on, it gets stuck at about 100 lumens, not quite a full 7135, but suspect the 7135 got blown.
I'm using the Hyperion FET, this one: https://www.arrow.com/en/products/bsc009ne2ls5atma1/infineon-technologies-ag. It's the first time I've tried it, was hoping it's as good as the SIR404DP. I am using the raptor claw 7135, and I used 10 uF caps for C1 and C2, the good LDO, and used a value if 4.7 uF for C3, and 0.1 uF for C4. C3 is between Batt+ and ground, before the R5. C4 is situated between LED- and ground.
I think we were hoping the C3 and C4 mods would prevent blowing the 7135 by reducing spikes, but maybe the FET here is the unknown. Maybe heat is a concern.
So, this has 3 XHP70.2's. When it blew, I was using fully charged VTC5A's (best high amp 18650 cell there is), and read just over 16,000 lumens but have no clue what the amps were. Since I know ~18A for one XHP70.2 ia bout 9,000 lumens @start, 16,000 lumens is "only" 5,350 lumens per LED.
I'm using fairly long 20 AWG wires to each LED, no psinrg bypasses but the driver spring is doubled (stock springs), and the battery tube has thick springs, but no bypasses.
Hi Tom, will have to catch up a little with this. Your part selections seem good though.
The 7135 seems to do OK with the inductive spike abuse in 1 S, so with the addition of C3 and C4 I would still expect them to survive in 2 S.
The long wires for sure does not help. And then there is just the sheer power (amps) in these builds.
add C3, C4. Is this right? For 2S
Steel_1024: Not my board, but from the photo C4 looks good. C3 does not.
- C4 forms an RC-snubber across the FET (R being very small, just parasitics).
- C3 is for bypassing, to limit supply fluctuations related to current pulses, cell wiring and cells internal resistance. It sits across the incoming feed to the driver.
Tom, for the lone 7135: Was wondering if the 7135 is more vulnerable when its gate is high. You might want to try keeping the 7135 off while the FET is working.
Yea, Steel's C3 did look suspect. Loooks like it goes from Batt+ to Batt+ (LED+ to LED+), but wasn't sure.
Hhmm - interesting idea for running them independently... Means a different ramping table I suppose, not sure how to do it actually. I was doing a bunch of testing with ramping at the time.
For the ramping, think I'll just take my best shot at it, then fully test it, then worry bout the smoothness later. Thanks!!
Are the A705NGT’s Mike C mentioned in post 63 in the Q8 modding thread any better than the 7135’s?
Lexel found them here. http://www.ebay.com/itm/10PCS-A705NGT-330-Encapsulation-SOT-89-/132216716613#shpCntId
I ordered those, but no clue what I ordered. I didn't even know a Q8 modding thread existed - weird.
Just read up on them in that Q8 mod thread, sounds very interesting at 12V rated - maybe it will do the trick after all. We'll see. Shippping is slowww, think still in China or on the way.
Ohh - datasheet here: http://www.datasheetlib.com/datasheet/1130180/a705_add-microtech.html
So it looks like I ordered the 330's, which are 330 mA. They do have a part # for the 350 mA version.
You and the monsters you build are the ultimate testing grounds. If they survive Mountain Electronics might consider stocking them.
Maybe they can replace the 7135’s in single cell lights as well.
Yea, I should really run them through a barrage of tests. Would be great to find a more reliable replacement. At 50 cents each, they are back to the high price though we all once paid, back when Illumn.com was about the only place you could buy them. But we'll see in higher qty. If they work out, I'll have to check for other sources.
Ohh - datasheet here: http://www.datasheetlib.com/datasheet/1130180/a705_add-microtech.html
So it looks like I ordered the 330's, which are 330 mA. They do have a part # for the 350 mA version.
Oh boy... These are as bad as the regular 7135's, maybe worse - specs are sketchy, only place I could find to buy them was on this one ebay site.
Amazing what pops up when you go trawling around with this stuff:
An 8V to 30V, 1.2A SOT-89 switching buck driver IC I’d never even heard of… complete with the usual sketchy “datasheet”:
A705x，x= 350mA
I can send you 20~30 to try, but there is no moon.
Does anyone know what the number on the second line mean on the 7135 chips. Everyone I find seems to have a different number.
I dont know what current these pass through but do have the claw on them.
Not sure what you mean by there is no moon. With Narsil/NarsilM, you can set the level of moon mode yourself in the configuration UI. Are you saying only the default level does not work?
Doesn't matter much to me if we have to bump up moon mode level by a 2-3 PWM values, but more than that is more effect, but probably ok - it all depends..
MrsDNF - yes, though are the classic good ones, but they are also the ones I've been blowing up on the 2S high amp mods. But the thing is will you get the ones as pictured?
I test A705X on MF-01 2S, 2P3S all 18 LED
I adj moon level to 7
No moon light still
Ok, then probably the PWM's speed would have to be slowed down for moon - TK and I have done this before and it works for other 7135's. Again, you are on the bleeding edge here - these things need to be tested. New parts need some R&D, and they simply may not do the job. Maybe the one A705X won't do - might need 2-3 for example, which still isn't bad, and do-able.
Are those 350 mA A705X parts available for me to buy somewhere? Only on Chinese sites?
A705X parts bought from China Tao-Bao chinese web.
I can order some for you, PM
On ebay, A705W 330mA
May be able to ask the seller, the seller should also be able to find A705X