Anyone worked with either of these drivers from Lightmalls?

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ohaya
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wight wrote:
ohaya wrote:
wight wrote:
Thanks ohaya.

Based on his post above, I think Slim Pickens may have been specifically interested in the size of the toroid itself (the donut shaped piece) without the wire wrappings.

I know, but winding is pretty tight. I might be able t o get the OD, but not sure about the ID.

Separate ques: Do we have enough info to know if this could do 4 amps?

I see what you mean. Maybe an accurate figure for wire thickness would be useful instead?

I think 4 amps could be a bad idea. The freewheeling diode (SS34) is not OK for that current, and I think the little shrimpy FET is also not going to be a fan of the higher current. You may be able to run this thing that way, but your losses will be high and if you get a failure it won’t be a surprise. Also, pushing a buck driver too far can zap LEDs due to spikes in the current. In short: no, do not do that. Smile

Ok, ok, MOM :)…

Earlier, you were thinking 3.15 amps… is that still attainable you think?

And yes, I can measure the winding wire diameter then.

wight
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I wouldn’t sweat ~3A, whether it’s 2.8A or 3.2A or whatever. Not everyone agrees with my decisions though and I certainly don’t know everything. There is a lot of unknown stuff happening in that driver.

Those tiny parts just don’t look like 4A would be their friend. For that matter they don’t really look like >1A would be their friend though, so who knows.

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

ohaya
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wight wrote:
Slim Pickens wrote:
Now we just need to see if blinkies can be nixed easily.

I wrote a fairly long post about this, but lost it after the forum went down for that unexpected maintenance.

I don’t have much time now to re-write it, but here we go while it’s still semi-fresh in my mind. The PWM / Modes chip does not seem to be the common CX2829, who’s pinouts appear to be:
1. modes?
2. GND (or modes?)
3. modes (or GND?)
4. PWM out / LED drive
5. offtime cap
6. Vin
Ref:
Group Buy for the GearBest Ultrafire F13 post #22
http://www.chipmaker.ru/topic/95167/

As we can see from ohaya’s pictures, pins 3 and 4 appear to be “not connected” on the unmarked SOT23-6 package. If that’s correct it can’t be CX2829.

The pinout we appear to have on this driver is (guesswork!):
1. Vin or PWM (probably Vin.)
2. GND (sort of…)
3. NC
4. NC
5. offtime cap?
6. PWM or Vin (probalby PWM)

Assuming any of that is correct, pins 3 and 4 probably need to be pulled to GND or Vin in order to change mode groups, if it’s possible at all. If ohaya will set the driver on “medium” and probe those pins for voltage with a DMM we can get a better idea what’s going on and then recommend an action.

So we’re talking about the 2 pins on either side of the end of the chip away from the dot, right?

When I try to measure pins 3 and 4 voltages, what do you want that relative to? Is the ground ring ok?

wight
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Yes, 3 & 4 are the pins farthest away from the dimple.

Unfortunately I’m not 100% sure what’s going on there. We’d better start by measuring everything against the outer ground ring, but we may end up measuring against that big crescent shaped trace that everything* seems to hook up to. I don’t really understand the purpose of the separation between the “true” GND ring and the other one unless it has to do with implementing the Zener diode.

*This is what I mean by everything:
303 resistor
104 resistor
cap
W8 diode
S4 diode (err, I guess it’s not hooked up to the crescent)
cap / white thing
R200
AOEC #2

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

ohaya
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Hi,

Toroid OD (NOT incl wire, I think): 8.05 mm
Wire diameter: 0.30 – 0.40 mm (I took several measurements, I think some parts of the wire was near where it was soldered)

Voltages to (emitter side) ground ring with driver in medium mode:

Pin 3: 4.18V
Pin 4: 0.115V

EDIT: My resistors shipped from Digikey (25 0.1 and 25 0.2 ohms)

wight
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We really need to see all 6 voltages for best results. (I’ll most likely still be guessing though!)

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

ohaya
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wight wrote:
We really need to see all 6 voltages for best results. (I’ll most likely still be guessing though!)

Aack! I interpreted what you said as just needing pins 3 and 4:

Quote:
Assuming any of that is correct, pins 3 and 4 probably need to be pulled to GND or Vin in order to change mode groups, if it’s possible at all. If ohaya will set the driver on “medium” and probe those pins for voltage with a DMM

NP, I’ll try to do all pins, but probably not tonight…

wight
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Sorry, poor choice of words on my part. I look forward to your results when you get a chance.

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

Slim Pickens
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Thanks for those dimensions, ohaya.

ohaya
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Resistors arrived from Digikey today:

You have to love Digikey (seriously)…. does that packaging look like a bit of overkill or what – I included the pen in the pic for scale :)!!?

ohaya
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I haven’t been able to get all the voltages on the 6-pin chip yet (couldn’t get to the one side w/o possibility of shorting something), but here are voltages to the (emitter side) ground ring with driver in medium mode that I have so far:

Pin 3: 4.18V
Pin 4: 0.115V
Pin 5: 3.12V
Pin 6: 0V

FYI, the resistors arrived, so I put 2 × 0.1 ohm resistors (R100) in parallel, and the current to the emitter goes to 4 amps at about 5V and above. I have one of those laser thermometers, and checked various points on the driver, and temperature seemed about 80F.

I tried a short test where I cranked the Vbat/Vin up, but I thought that I saw some smoke, so I shut it down.

The driver still worked after that, and I visually inspected with a 30x magnifying glass and I didn’t see any obvious (to me at least) signs of damage. Also, there wasn’t any “burnt smell” that I noticed, so maybe I was just imagining it.

LowLumen
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We know the SS34 Diode is only rated to 3A max continuous, so that is one part I would be watching for the magic smoke to get out. Maybe look for some bigger diodes in the parts drawer.

ohaya
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LowLumen wrote:
We know the SS34 Diode is only rated to 3A max continuous, so that is one part I would be watching for the magic smoke to get out. Maybe look for some bigger diodes in the parts drawer.

I kind of suspected the SS34, since that’s the part that got kind of lifted off of the board when I pulled the R200 earlier, but it (the SS34) still looks ok (no blistering/bulging, no burnt odor), but it’s possibly on the underside, that I can’t see.

Would these work, both electrically and size-wise:

http://www.ebay.com/itm/20x-B54-SMC-DO-214AB-1N5825-SMD-5-0A-Schottky-Rectifier-Diodes-NEW-/251095507434?pt=LH_DefaultDomain_0&hash=item3a767561ea

??

And if they do work, does that mean I’d be able to run 5 amps?

EDIT: According to this, the SS34 is DO-214A package also, correct?

EDIT 2: What about this one from Digikey (the qty 1 one, not the qty 3000 one)?

http://www.digikey.com/product-search/en?KeyWords=SK510L-TP

ohaya
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I was just thinking of something (it happens once in awhile), and have a stupid question: How is it that the MCU on the 16mm driver doesn’t just get fried when I, say, put 9V input?

wight
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I’m not sure MCU is the proper term for that thing. Regardless of the terminology, I think the answer is that a zener diode is used to power it. Google has simple diagrams for a zener and resistor together, that is the arrangement I’m referring to.

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

ohaya
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wight wrote:
I’m not sure MCU is the proper term for that thing. Regardless of the terminology, I think the answer is that a zener diode is used to power it. Google has simple diagrams for a zener and resistor together, that is the arrangement I’m referring to.

Ahh. Ok, so it’s similar to what comfy does with the 7135-based drivers, i.e., use a zener to drop the Vbat/Vin to a voltage that the MCU/controller can work at.

Any idea if that diode I linked at Digikey could be swapped into the driver and let the driver work at 4amps?

ohaya
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FYI, I’ve gone ahead and ordered a couple of the SK510L-TP diodes from Digikey and will try to swap them onto one of the drivers and see if it’ll run at 4 amps (or maybe more, I also order some 0.05 ohm resistors :)).

EDIT: Pretty soon, I’ll have enough parts to build these drivers from scratch like you all do on the Oshpark projects :)!!

wight
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We’ll see how it goes. I suspect that the best case scenario is that efficiency is quite low with the tiny FET. :~

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

ohaya
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wight wrote:
We’ll see how it goes. I suspect that the best case scenario is that efficiency is quite low with the tiny FET. :~

This whole thing should be interesting, huh? I have a few places where I can/would really like to use a tiny 4A, 2 x Li-Ion driver awaiting.

wight
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ohaya wrote:
wight wrote:
We’ll see how it goes. I suspect that the best case scenario is that efficiency is quite low with the tiny FET. :~

This whole thing should be interesting, huh? I have a few places where I can/would really like to use a tiny 4A, 2 x Li-Ion driver awaiting.

Yeah, I know exactly what you mean. I think a fair number of folks here really want a small, powerful buck driver. I’m definitely on the list. After we’ve got that hammered out I suppose the only thing to do is focus on a small, powerful boost driver Wink

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

ohaya
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wight wrote:
ohaya wrote:
wight wrote:
We’ll see how it goes. I suspect that the best case scenario is that efficiency is quite low with the tiny FET. :~

This whole thing should be interesting, huh? I have a few places where I can/would really like to use a tiny 4A, 2 x Li-Ion driver awaiting.

Yeah, I know exactly what you mean. I think a fair number of folks here really want a small, powerful buck driver. I’m definitely on the list. After we’ve got that hammered out I suppose the only thing to do is focus on a small, powerful boost driver Wink

I know that I’m a bit slow on the uptake, but after working with this for a few days, I’m now understanding (seeing the possibilities more clearly) of the buck driver!

I can’t wait to see how the new diode works out and if I don’t kill the drivers!

LowLumen
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While waiting for your 5A diode, you could set it for 3 Amp and do some measures to see how well the driver is handling that load: Voltage and Amps in, volts and amps to the LED.
The efficiency will tell you how much power is lost (heat) in the driver and if it is likely to be able to handle more current without smoking it.

ohaya
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LowLumen wrote:
While waiting for your 5A diode, you could set it for 3 Amp and do some measures to see how well the driver is handling that load: Voltage and Amps in, volts and amps to the LED. The efficiency will tell you how much power is lost (heat) in the driver and if it is likely to be able to handle more current without smoking it.

I had stacked 2 x R200 and 1 x R100 resistors earlier, on the 1st driver, and from this post:

http://budgetlightforum.com/node/32575?page=1#comment-617562

Quote:
I was seeing about 2.8 amps at the emitter from when Vbat was at about 4V+!

So, I think I can just go back and get those numbers with that driver, and it’s close enough to the 3 amps you were suggesting?

LowLumen
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… if you got the Voltage and Amps on the input (battery/power supply), and the voltage & amps on the output/ LED at the same time, then Watts out/watts in will give efficiency.
I didn’t see all those numbers for the 2.8A test. Power lost in the driver will go somewhere; it will turn to heat.

wight
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In other words, LowLumen isn’t worried about exactly what current you are using. It’s a matter of collecting all that data he mentioned. Once you have that at 3A, 2.8A, or whatever, we’ll know power in and power out. The difference will represent losses in the driver (as heat), exactly as LowLumen stated.

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

ohaya
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Understand that guys :)…

LowLumen
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It will give some idea of how likely you are to smoke it by pushing it harder too. Try to be as accurate as possible with the measures. If you are using a clamp meter on the LED current, try looping the wire through the clamp twice & /2 on the reading for better accuracy.

….well, I like efficient drivers too :bigsmile:

wight
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ohaya wrote:
Understand that guys :)…
Sorry son, didn’t mean to be pedantic. Wink :bigsmile: :bigsmile:

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

ohaya
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Hi, Here's the In vs. Out info:

VinIinPin (watts)VoutIout (x 2)IoutPout (watts)Efficiency %
30.631.89 2.840.80.41.136 60.1%
3.21.153.68 2.931.860.932.7249 74.0%
3.41.816.154 3.023.151.5754.7565 77.3%
3.62.258.1 3.063.991.9956.1047 75.4%
3.82.7310.374 3.094.962.487.6632 73.9%
43.2613.04 3.116.023.019.3611 71.8%
4.23.6315.246 3.126.73.3510.452 68.6%
4.43.8817.072 3.127.183.5911.2008 65.6%


Vin/Iin were what was displayed by the bench supply.

 

The table above was done as suggested, with one of the emitter leads looped through the clamp meter twice. 

 

Vout/Iout were measured using the clamp meter (again, looped twice) and a voltmeter attached to the emitter leads.

 

EDIT:  Sorry, I forgot to mention that this was the 1st driver, the one where I stacked R200, R200, and R300 resistors.

 

EDIT 2:  Emitter was an XM-L, on Noctigon, sitting on a (maybe) 1/4" copper plate with thermal paste.

 

ohaya
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BTW, there have been multiple mentions of the FET. Which component is the FET? Is it the 2 of them that are marked “AOEC”?

EDIT: It looks like the new diodes (plus a bunch more of resistors) will get here today via USPS.

I was thinking about this driver, and my question above, and realized that we, or more precisely, I, have not identified all of the components on this driver yet.

Referencing the pics at http://budgetlightforum.com/node/32575#comment-617348:

- We know the R200 is apparently the 0.2 ohm sense resistor.

- I think the SS34 is schottky diode.

- What is that “LEDA 1322” chip?

- What are the “A0EC” or “AOEC” chips?

- What is the “151”?

- What is the “W8”?

- What is the “S4”?

Anyone?

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