RGBW XML Driver mod.

[Conte]

I'm wondering if anyone else has done the mod that I jsut did.

I'm sure we are all familiar with the RGBW MCE and the common driver that is made for it.
I got mine from outdoor Intl.

And I'm sure most of you are familiar with the RGBW XML.

And it has been discussed that there is not matching driver for the XML and we are stuck using the MCE driver that under drives it.

Reference, The MCE is rated for 700ma, and the XML version is 1000.

I'm a technician by trade so I had a hunch . . .

I looked up the data sheet of the regulators that driver uses and noticed that they are generic adjustable regulators unlike the 7135's that are commonly used and can actually handle 3 or 5 amps or something like that, I forget off the top of my head.

When I got the driver I noticed there was indeed a bias resistor on each regulator to set it's output.

So what I did what figured out what resistance value I needed to set the driver to correctly run the XML.

The stock value is 911ohms and that gave me about 700-800ma tested between the driver and the LED.
I determined a required value of about 500ohm. I was able to find a 470ohm resistor of the correct size in my scrap.

I removed the stock resistor and installed the 470 and measured 1.3a drive to the LED.

Eureka!

I left the colour output values alone as I'm not concerned with them, but was able to mod this driver to run the white emitter into a slight overdrive sweetspot.

Doing a search on this forum I have not found any talk of this sort of mod to get the most out of the RGBW XML.

I figured it would be a good idea to share my findings.
I'm going to torture test setup soon.



Pic or it didn't happen:

 

[Conte]

Oh, as a follow up, this mod has worked out swimmingly.

It sustains the extra current with no problems I the build I did.

 

[jason 77]

COOL! I am going to try this with the driver I have from int outdoor!

 

[Lumencraft (Matt)]

Thanks for sharing this Conte.

 

[djozz]

I replied before, but my post appears removed (why?). Thanks again for sharing the mod, I will do this to my intl-outdoor driver as well

 

[djozz]

Tonight I did your mod and it worked like a charm. I have the XM-L colour in a modified cheap small 14500 battery zoomie:

I had an identical RGBW-driver leftover that I had killed someway and I scavenged the 911 Ohm resistor from that one and piggybacked it on top of the other resistor, that should result in 455 Ohm:

I do not get the promised 1.3A, but on a Efest IMR 14500 I do get 1.1A, with an output on white of 150 lumen. It was already one of my favorite mods, but with that little bit of extra output on white I like it even better! Thanks again for the tip.

 

[Conte]

That's awesome. I'm glad someone ha s made use of this. It s such a simple mod I'm surprised some places selling these drives don't offer them pre modded.

Anyway, I can't say I promised 1.3a. That's just what I got on my sample. I'm not even sure if the resistor is exactly 470 ohm.

I'm fussy about my wiring and having a clean current path and have the skills to make it happen. Notice how clean my led wiring is. Add that to the fact I'm running it off a 26650 imr cell and that could explain the variance.

I found that it's not hard to loose current on a diy led build, hell I've lost more than that just in my meters crappy probe wires. There is a chance that the assembled light is rocking 1.3a or more.

 

[Johellin]

Great post, and great idea.
Those LED-drivers, are they PWM-controllable to get smooth dimming? And do they control all the colours separately?

John

 

[RoGuE_StreaK]

Those LED-drivers, are they PWM-controllable to get smooth dimming?

Doesn't look that way if the below is the driver Conte's talking about, unless there's a hack out there.
http://intl-outdoor.com/mce-color-and-dynamic-white-20mm-driver-p-687.html

And do they control all the colours separately?

As per link above, the way I interpret it it cycles through the colours on mode change (or flashes through them in another mode), not mixing them.

 

[Conte]

Great post, and great idea.
Those LED-drivers, are they PWM-controllable to get smooth dimming? And do they control all the colours separately?

John

No, this driver does not dim at all.
It's single mode as far as output goes.

It simply turns on the die of the selected colour. With some various store modes at the end.

No memory, it always starts on white.

 

[gamezawy]

can this mod be done for the other colors ? to achieve 1A or more ?

 

[Lumencraft (Matt)]

I dont suppose anyone has written some code for this micro that would add a memory perhaps? I could use the heck of of this driver if it would come on in the same color I last left it.

 

[Conte]

can this mod be done for the other colors ? to achieve 1A or more ?

According to my research the regulator chips are rated up to something like 5 amps. So, yeah, in theory, if you lower the resistance value even more, it would pass more current.


However, a linear regulator of this type tends to generate heat as the load increases, so I imagine you can only push it so far before it overheats.

And yes, each colour has it own reg chip, each biased with its own resistor, so you could boost the output for all the other colours, except that it may defeat part of their purpose.

 

[Conte]

I dont suppose anyone has written some code for this micro that would add a memory perhaps? I could use the heck of of this driver if it would come on in the same color I last left it.

No idea, that would be sweet tho. Dimming modes too.

 

[Dr.Jones]

If remember correctly, this MCU is a noname without any imprint, probably not even reprogrammable at all like quite a lot of those.
For electronic switches I have a suitable driver with arbitrary color mixing, see here

 

[Moss]

I've just finished a mod using the XM-L with a driver from Mountain electronics http://www.mtnelectronics.com/index.php?route=product/product&path=67_124&product_id=90

I think that it was the last one, as now they've sold out. Does someone know where to purchase a driver for the XM-L RGBW? does not have to be the same, above I saw that you were talking about the possibility of mixing the colours, is there any progress on that? would be super cool.