Guess I’ll just have to get a SIRA00DP and try for myself.
Sorry, that was a roundabout way of saying I don't know how the specs (the gate characteristics) will affect things since I don't know yet how the 404DP will behave.
But at a glance, it doesn't look promising.
SIR800DP: (works)
| Gate Charge (Qg) @ Vgs | 133nC @ 10V |
|---|---|
| Input Capacitance (Ciss) @ Vds | 5125pF @ 10V |
SIR404DP: (probably works? maybe?)
| Gate Charge (Qg) @ Vgs | 97nC @ 4.5V |
|---|---|
| Input Capacitance (Ciss) @ Vds | 8130pF @ 10V |
SIRA00DP: (???)
| Gate Charge (Qg) @ Vgs | 220nC @ 10V |
|---|---|
| Input Capacitance (Ciss) @ Vds | 11700pF @ 15V |
It doesn't help that those aren't directly comparable since they are not at the same voltages (and also especially that I really don't know what happens when the gate specs don't play nice with the MCU).
Cool. I’ve just made a version of my FET driver (Mod: My take on the convoy S series with side switch mod.) with the PowerPAK SO8 and ordered some samples from OSH Park. I’ve got an order ro place on Farnell so I’ll just add a couple of SIRA00DPs, stick ’em on and see what happens.
The SIRA00DP works but doesn’t put out as high a current.
Apples to apples it might do 4.2A while a SIR800DP does 5.3A.
I did try some, great if max amperage isn’t required and probably a good option for those situations where a light is going to be used with a protected cell.
Thanks DB!
I got some to compare with the SIR800, built X6 lights with everything else being the same, literally. The output on the SIRA00DP was disappointing. The PSMN0R9 was very similar on a fresh charged cell , very close to the SIR800DP, but when the cell runs lower then the SIR800DP pulls ahead. Richard has found this to be true as well and highly favors the 800.
Found the notes…
Built 3 X6’s with XM-L2 U2 3D emitters out of the same tape. Samsung 20R cells at 4.22V
It wasn’t so much the amperage as it was the output…
SIRA00DP 4.59A at 1169.55
SIR800DP 4.59A at 1373.1
PSMN0R9 4.63A at 1373.1
Differences exaggerated as the cell dropped power.
Sharpie, was it on an Aluminum star? That’ll do it every time…
Yikes. Yeah, I’ve done that to the little mosfets and I certainly do hate that smell. Do the little rectangles have the implosion dot on top? lol I actually got a new light once that had a massive brass pill in it. It stunk of that electrical burn. I know good and well it had been blown and returned, the driver actually had some burned components still on it as though they didn’t even bother to put a new driver on it, told me it was the last one available and sent it. I, of course, put an FET in it with an MT-G2 and except for the smell that’s in that brass to this day, never looked back.
I know the older XM-L2 can take up to 8A, usually, but apparently the XM-L can’t go that high. I seem to recall really liking the T6 versions of XM-L, I’ve got a bunch of old ones sitting in my kit that have been removed but of course not much way to identify them. My UV light can get me close on the tint bin I guess, after that power level would pretty much sum up the bin.
I think you’re right about the XM-L being great for 3A and under, even maybe 4A in a certain kind of light, so maybe they aren’t quite as capable as the new ones, they’re still nice emitters. Everything doesn’t have to be hot rodded. Just everything mine. 
Keep reading, you’ll get there. 
For FET selection for use in single cell (or 1s4p & etc) lights the RDS (on) vs VGS graph, or another graph containing similar info, is a primary factor for obvious reasons. Low RDS (on) is good of course… Clearly as long as we have a lower resistance than the equivalent wire length there’s not much gain to be had. When comparing SiR800DP and PSMN0R9-30YLD the graphs for RDS (on) vs ID (so top of page 3 and Fig10 on page 8 respectively) are very telling. The rest can either be seen in the specs table or with a scope…
FWIW I think you may have keyed off of comfychair’s comment. Remember that comfy’s very skilled but also hit and miss on driver knowledge - and just back from an approximately 1-year break from the forum.
I don’t want to sound mean about this, but we are quite aware that cells are a major limiting factor! For many of us this sort of information is quite mundane (especially in a thread like this one). You must have noticed all the discussion of high drain cells and the results they provide in ‘XYZ’ DD light? That’s not monkeys and typewriters…
Springs are another major limiting factor, that’s why we bypass them for these lights. You’ll find that if not bypassed at high currents they simply fail. Switches also have high losses, so some builders use the best switches they can. Another solution is to use momentary/e-switch lights where that’s no longer an issue (Tom E’s preference).
In terms of your burnt XM-L… you’re doing it wrong. I’ve personally measured an XM-L at 9A in short bursts - repeatedly. That setup went into a P60 which is still duty-carried with a cell that can make 9A through the LED. It’s got instant turbo rampdown, but the turn-on is always at 9A. I probably should have dialed it back, but I didn’t and it still functions. (Djozz has done considerably worse things, but not to the old XM-L.) Your missing ingredient is DTP. FWIW IIRC XM-L has higher current handling, old XM-L2 has high current handling, and new XM-L2 has mediocre current handling. (3 bond wires, 2 bond wires, 2 weaker bond wires)
At the end of the day, having some limiting resistance for a DD light is sometimes a good idea. You’ll see folks do it here. DD does mean that “any old cell” is never suitable - a [hypothetical] high enough drain cell will kill any 3v LED.
EDIT: Oops, looks like DB beat me to it. If you killed the XM-L while it was on a Noctigon mounted in a light… I suspect that your meter simply wasn’t fast enough to show the actual current. (Not enough solder on the thermal pad can also be a problem of course.) I added some strike-through since you’ve already ruled out my prime suspect.
EDIT2: I’ve destroyed more parts by “foolishness” than anything else. 
Believe it or not, I am actually getting somewhat bored with the pursuit of maximum output. I do have a few lights of recent build that I focused on quality more than quantity. Even dialed back my Texas Poker with a Nichia emitter for the more pure spectrum of light offered. The beam profile is now gorgeous and I’m very happy with it again. At under 800 lumens. (What? You didn’t think I was going to say a couple of hundred or something did you? )
My Intimidator is “only” making about 5000 lumens on it’s 96CRI XHP-70, the parts that once had it making ~650Kcd are in the box.
I have plans to build a 20,000 lumen light, but frankly it’s not as exciting a concept as it was when I ordered all the metals to build it, so I haven’t started. Weird, when you think about it. I haven’t even finished my Marvin the Martian green laser ray gun, and it’s about 55% complete.
Maybe it’s time to silver solder a stack of old silver half dollars together and machine a pure silver flashlight…
Cool! Sounds like a nice find. I don’t actually have a Sky Ray King, I have a Rook though. Wonder if that one you got is still available?
No need to wonder, we have data. Besides what Cree provides members such as djozz and match have generated good information.
RMM’s also been pretty specific that he gets better output despite higher vF due to the increased output from Cree’s newer stuff. The big downside of course is that with a high forward voltage CC regulation on a single sell becomes difficult. Doesn’t apply to this driver, but high current linear and buck drivers are left out in the cold.
Where did you order your SRK (kung) from? Does it include a screw-in shelf which the MCPCB sets on? If it’s a reliable source at a decent price I’m sure a few folks would be interested. It is surprising that a relatively well made light also has genuine XM-L emitters at this point.
Probably an original, old stock, Wight. One of “the good ones”
The interesting thing is that it’s using an FET driver with an SO8 FET. That didn’t happen for quite some time. The “original” originals all used a 3-channel buck driver. Next there was a wide variety of drivers in the various clones, imitations, or simply new production units (IIRC). Eventually the JB driver showed up and that was using a TO-252 packaged FET (eg the big one). Eventually a modified version of the JB driver finally switched to SO8, probably due to the cost at that point (SO8 had long been “very common” for commercial stuff by then!). By that time (January 2014 we’ll say) I think that the flood of poor SRKs was well underway.
I figure the lumens per watt will keep increasing over the years until we get close to 300, and batteries keep getting stronger, so anything I build now for maximum lumens will become obsolete. However, if I make something nice now, it’ll still be nice later… just not as efficient as it would be with newer parts.
A nice host stays nice a lot longer than the engine inside it, so I’ve been choosing items mostly based on the host.
Plus, I only want up to 50 lumens most of the time anyway. I doubt that’ll change any time soon. I can do most of what I want with 1x7135 and an attiny13a.
Yes, the tailcap and cells are important factors. This discussion kind of assumes everyone has already installed the hottest cells and bypassed all springs and otherwise eliminated as much resistance as possible in the host. Take it as a given that every other possible factor has been maxed out, and the focus is on only the driver.
So, what’s left to improve? The FET is an obvious target for optimization, and there are still a few models which haven’t been tested yet.
We have models? Parade a few of em out over here if you don’t mind…
Wight, Comfy, you might be interested in this…
2 Eagle Eye X6 hosts, all pieces parts to start with. 2 A17DD-S08 boards, ATTiny13A flashed with A6 firmware. (I know, I know) 2 of the XP-L V6 1D out of the same tape, side by side. Same wire length, 20ga Turnigy, everything built identically. Same sized bits of solder paste when putting the switch on the pcb, same goes for the springs. All stock, NO bypasses whatsover. The 2 driver boards had to be separated, as did the 2 SinkPAD 20mm stars, everything was from the same tape, side by side, as identical as I could possibly make it.
2 brand new never put in a light Samsung 30Q, rested at 4.20V.
SIR800DP
5.96A for 1538.7 Lumens
1407.6 at 30 sec
2.71A for 793.5
0.97A for 314.99
0.10A for 42.88
0.01A for 3.07
0.01A for 3.07
SIR404DP
6.01A for 1607.7 lumens
1476.6 at 30 sec
2.74A for 821.1
0.99A for 327.75
0.11A for 44.99
0.00A for 0.828
0.00A for 0.828
My meter wouldn’t show anything on the lowest modes of the SIR404DP, stayed solid on 0.00, which is unusual.
No single 7135, no moon mode, each light has 6 instead of 7 modes, each light does the same on level 2 and 3 , in other words, 1 is blank, 2 and 3 repeat, then 4,5,6,7.
What PWM values for each mode?
From the A6 C file…
// Mode group 1
#define NUM_MODES1 7
// PWM levels for the big circuit (FET or Nx7135)
#define MODESNx1 0,0,0,7,56,137,255
// PWM levels for the small circuit (1x7135)
#define MODES1x1 3,20,110,255,255,255,0