I'm using 16 XHP50's so it's a lot more power than 16 XP-G2's. The FET I chose, the SIR404DP is capable, but I'm having problems with the 7135. I added a grnd jumper to help in heat, and added a heat sync on top of the chip, and it's surviving now, but not working normally - delays coming on, sometimes doesn't come on at all.
Don't have time to trouble-shoot it further now. Might get back to it, or eliminate the 7135 altogether
Well i found PH4030AL as a FET candidate, i think i’m on the right track.
Considering the 7135’s low power rate, what’s its purpose on circuit at all? “Supports” the FET or something?
PWM'ing FET's works great, specially at high PWM rates, but say for example you are getting 6 amps out of a FET on full, PWM'ing the 6A means you are pulsing 6A constantly. The way the 7135 works is it limits output to 350 mA, so to get 350 mA out, just drive it at it's fill capacity. So instead of continuously spiking 6A out, you get a smooth consistent 350 mA of output. This works way more efficiently than PWM'in a FET to get an equal amount of light output.
So we use FET+1 circuits/drivers for this reason. If you PWM the 7135, you get very efficient low modes, all the way from less than 1 lumen up to about 150 lumens.
Take that one step further like HQ did on this board design, add in a bank of 7135's and you get 3 output channels: 1 7135, bank of 7135's, and a FET. This way you get efficiency out of the middle modes as well, using the bank of 7135's. Wiring 7135's in parallel effectively adds them for total amps output. 8 7135's is 2.8A, 16 7135's is 5.6A, etc.
Bout that FET, there's a few things to look for. DEL and a few other BLFers could analyze the specs wayyy better than I could. I don't take the chance - I only use what's been reviewed, and then proven.
Hi cherkess_jan,
You find the formula explained in the STAR firmware of member JohnnyC:
VOLTAGE
Resistor values for voltage divider (reference BLF-VLD README for more info).<p>Reference voltage can be anywhere from 1.0 to 1.2, so this cannot be all that accurate<p>VCC
|<p>Vd (~.25 v drop from protection diode)
|<p>1912 (R1 19,100 ohms)
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|---- PB2 from MCU
|<p>4701 (R2 4,700 ohms)
|<p>GND
ADC = ((V_bat - V_diode) * R2 * 255) / ((R1 + R2 ) * V_ref)<p>125 = ((3.0 - .25 ) * 4700 * 255) / ((19100 + 4700) * 1.1 )<p>To find out what value to use, plug in the target voltage (V) to this equation
R1 and R2 are a voltage divider, the voltage that is measured by Pin7 of the Attiny13a has to be brought below the reference voltage of this MCU which is 1.1V. Values below 1.1V result in a value between 0 and 255 which can be translated to a certain voltage at Pin7 and its equivalent, the cell voltage.
This is used to recognize when the voltage is below a level critical to the cell (to get low-voltage protection) or to measure and blink-out the cell voltage in general. In your case, planing with a fixed voltage power supply, I can’t see the need for measuring the voltage. But if you want to do so, you will need a divider that brings 12V down to 1.1V, so R1 should be roughly 10-12x the value of R2.
Sorry if some comes double with what TomE already wrote, but I had written the answer before I read his and now I just copy-paste :innocent:
I might have said it before, I haven’t heard of someone using this driver with 12V, it’s designed for single cell (1S, 4.2V) and prepared for 2 cells in series (2S, 8.4V), which already gives problems with the 7135s. I wouldn’t bet that 12V will work, perhaps as a FET-only driver. But if you get it working, be sure to let us know. :laughing:
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And here’s a teaser for TomE.
Yes, those are 70 LED+ vias and they don’t have soldermask. 
And some more optimizations for high current, might that be of any use?
I just have to double-check the oshpark preview and finish the doku.
And the tabs, of course.
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I went with brass for contact rings as well, by the way. More durable, less weight, probably even easier to solder.
Downside of these is they are stamped out, so they are not completely flat. But they are 34mm outer diameter which is perfect for button top cells.
I admit that I prefer not to fill the vias with solder, so I milled a larger center hole and will use a board with LED+ vias inside this ring.
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Wow!! Nice!! Agree - brass is the best choice there. Based on the amps I'm pumping thru it, it sure can take them. I believe SupFire and others also use brass for the contact ring.
For 12V for 7135's, Richard (MtnE) emphatically said in the past that 7135's will not work.
BLF SRK FET v3.3 Jester
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So here I am once more
In the playground of the eagle boards
One more experience one more entry
In the oshpark profile…
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https://www.oshpark.com/shared_projects/JuAe4zh2
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Inspired by DEL I went back to the idea of having the LED- path in front of the 7135s and revived a design of half-circles that I had already tried somewhere along the way.
The schematic of v3.3 is the same as v3.4, any further detail is the following post.
BLF SRK FET v3.4 HiPower
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Based on v3.3, but with focus on high current.
Still triple-channel, LFPAK56, Attiny13A/25/45/85 and DEL’s R5.
Adding indicator LED at Pin7 and layout improvements.
I kept the QuadPad to still be able to use dual-channel firmware.
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Changelog from V3.2
To fit the needs for high current applications:
- 70 LED+ vias without soldermask
- more GND vias
- Wider current path from GND ring to FET source
- better heat transfer for Q1
- Increased GND plane
Other improvements:
- Added Ri7 and I7 for indicator LED at Pin7.
- Added 1 AMC7135
- Added a bleeder resistor from BAT+ to GND
- Reduced size of QuadPad to standard 0805 size
- Removed dedicated Rgate, as the gate resistor fits on the QuadPad and can be used instead of a zero-ohm-resistor between FET and MCU
- Redubbed Rmcu to R5
- Marked in/out for LDO
- Just one place for R1 and one for C1
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https://www.oshpark.com/shared_projects/4trVY7MM
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Schematic:
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Component list:
- 13A/85: MCU ATtiny13A or 25/45/85; 8S1 (SSU) or 8S2 (20SU)
- R5: Series resistor between VCC and MCU Pin1; 0805
- FET: N-Channel MOSFET at Pin3 or Pin6; LFPAK56
- (Rgate): Series gate resistor; use the QuadPad (FET-to-Pin3 or FET-to-Pin6); 0805
- Rpldn: Pulldown resistor (gate to GND); 0805
- Q1: Single AMC7135 at Pin5; SOT-89
- Q2-11: Up to 10 AMC7135 at Pin3 or Pin6; SOT-89
- D1: Schottky diode (~0.25V) for 1S (4.2V); SOD-323
- LDO: Low dropout regulator for 2S (8.4V) [LDO needs C1 and C2]; SOT-23-5 (Vout is pin5)
- C1: Input capacitor between Vin and GND; 0805
- C2: Decoupling capacitor for MCU; 0805
- R1: Voltage divider to VCC [before D1 / behind R5]; 0805
- R2: Voltage divider to GND; 0805
- Rb: Bleeder resistor from BAT+ to GND; 0805
- SW+: Pad for momentary switch to Pin2
- SW-: Pad for momentary switch to GND
- Tin/Rt1/Rt2/T+/T-/Ct: Temperature sensor
- I3/Ri3/I-: Indicator LED at Pin3
- I7/Ri7/I-: Indicator LED at Pin7
Notes:
- Rt2 can be used as Nanjg Star 3
- OTC can be used as Nanjg Star 4
- A Zener can be placed on Ct, which is MCU+ to GND
Very nice work HQ!
Again, very impressive!! Might need a version slightly wider, 2 screw holes, but, you got time for that... 
Love that ‘Nike swoosh’ for LED- on the Jester!
Just ordered a set of 3. Boy these boards are perfect for the MT07 and MT03 lights - they use standard SRK size drivers. LDO and away we go...
Your driver, these lights, and XHP70.2's were made for each other!!
I recv'd these boards a while back - no time to try them out though. Realized though a big problem to use them in a MT03 or MT07 -- the batt+ pad needs to be centered and way smaller. Thinking if some way to use it - scrapping off, prying up up a large amount of center tracing, and/or use of kapton tape. Actually I think would might work:
add solder to the grnd ring so it makes contact to the battery holder ring first, preventing contact to the batt+ center pad. Think if I keep the solder really low and kapton tape the outer part of the batt+ pad, that might do it.
Ooops - totally wrong bout this. Forgot about the solid driver retaining ring of the MT03. It fits perfect as-is, ground ring contacts well and the Batt+ doesn't make any inadvertent contact.
I just gotta figure or remember what cap values to use with the LDO, on the C1b and C2 pads... ?
Ooops Again - didn't realize the board layout totally changed from v3.2 to 3.4 - pads aren't even labeled the same... Oh boy... I can figure it all out I'm sure, just gotta figure out cap value again... Might need help from DEL. Let me check back thru this thread as well.
I looked at this driver
It is pretty odd that the Temperature sensors connection goes to the output of the LDO and ground
There must be some sort of circutry that disable the FET on the Tin pad and the 2 resistors nearby
Why is that odd? Dunno what a temp sensor supposed to get, but sounds like he's providing it 5V, I'm thinking? Suppose it needs a connection to an I/O pin of course, but none are available, which is why it doesn't interest me at this point.
I'm using these as 2 channels with enabling the indicator LED on pin #3 in the MT03 and MT07 - got all the parts nailed down, so will reflow soon.
Using DEL's new C3 and C4 to reduce the spikes the 7135 was getting. C3 will sit on the Rb pad, while C4 is from LED- to ground, so probably will use an empty 7135 pad to bridge to LED-/
HQ/anyone! I hit 27K lumens with this v3.4 driver in a MT03! Wow!! Great job on this. Dunno, maybe the Hyperion FET helps a little. Never expected 27K, than means 9K per XHP70.2 in a NW tint! It's totally insane!
I added spring bypass's of 22 AWG wires on all 4 battery springs, and left the double spring on the driver as-is, just transferred them to the v3.4 driver of course. It ripped the 60C temp setting at like 15 seconds - ouch.
Oh! The Humanity!
Tom. Are you going mad? Blinded by the light maybe? Nice work. 
Any pictures of install or beam shots?
WHAT! That has to be 55-60 amps your pulling! 
:+1:
Way to GO!! 
My MT03 is almost here and I would like to do what Tom E did. Any details would be appreciated.
I haven't been able to repeat that reading, but I was seeing 24K-25K, same cells full charge, etc. Still it's pretty awesome.
Ohhh - just thought of it - I swapped the FET to a SIR404DP, think'n it might fix the 7135 problem, but it didn't. It blows the single 7135 - haven't had luck fix'n it. I changed the firmware to do blinks with the FET instead of the 7135, so the blinks work. The 7135 seems to work fine in ramping and mode sets, just would be do any blinks.
I ordered another MT03 II so it's on the way. Gotta check now if I have a spare driver... Hhmm... I did order 3 XHP70.2 P2's from Arrow to use for it - just don't want to take the chance on the XHP70.2's shipped with the new MT03.
Do I have pics? No beamshots, but must have some build pics...
Full set here: photobucket.com Haikelite MT03