Driver Help

[baseballfanatic2]

First… thanks in advance for looking.

Can someone help me please.
I want to run a couple strings of leds off this power supply. Using ldd board.

how many Cree leds can I run per string?
also, is amps an issue on this driver?

 

[oreo54]

Adjustable current from 700 to 2100mA
30-56v
Which CREES?
CREE xt-E is rated at 1400mA @ 3.4V
Assume around 3.2V @ 1000mA.
1000mA is probably a good starting point for easier thermal management.

So 17 per series string.
Trim driver to 1000mA or less.
You can, though not usually recommended at least without circuitry complications,
run 2 17 diode strings in parallel and trim driver to 2000mA.

The LEAST that would need to be done (opinion) is add a fuse to each string at say 1.25A in the event of one string failing "open"
The fuse will protect the last string from taking the full 2000mA and possibly going into thermal runaway and failing.

There are other things one can do such as current balancing transistor circuitry or even IC's that improve overall success.
https://www.ti.com/lit/ds/snosb96f/snosb96f.pdf?ts=1623906182609
But it gets complicated.
Most DIY just settles w/ simple 1 driver 1 string topology.

Oh and minimum of 10 diodes to keep in the constant current zone.
Not seeing that the driver is dimmable btw.

 

[blasterman]

Spec sheet looks like a meanwell driver, but line 1 and line 4 contradict each other. Not clear if its 1400mA or 2100mA, and how specially is it dimmed.

If its a Meanwell can you tell us which one it is?

If it indeed 1400-2100 use XPG3s. They can take two amps as long as you have good heat sinking. Just don't run them quite full out.

 

[oreo54]

SLD-80-56

http://www.farnell.com/datasheets/2860313.pdf

And a BIG correction.. at 2000mA you are restricted to about 40V (39.2 to be more precise)


MY mistake.. need to honor the 78.4 watt rating.
see spec sheet

So 12 in series 2 parallel strings
12 x 3.2V= 38.4 x 2A x 1/2(current split) x 2 series strings =76.8W
OR 24 in series @ 1A
24 x 3.2V x 1A = 76.8

Best practice usually suggests leaving 10% as a buffer so really
70.56 W is the goal..

11 or 22 diodes.. 70.4W
whatever diode you use need to know approx V(f) at the current you want to use..

At 2A you are limited to say 39.2/ 3.6V (guess for now) 10 diodes in series.
10 x 3.6 x 2 = 72W.. ignoring the 10% fudge.

LEDs get more efficient at lower currents for the most part. Some by a little, some by a lot so "underdriving" but more diodes at a lower drive current but same wattage is a gain... but it gets to be a matter of cost at times.

Since I firmly believe in passive cooling I'd never max out the diode BUT it's a philosophy.. no more, no less.
1/2 max is a sort of rule of thumb for me, broken here and there.

Hope that's all correct.. a bit worn out atm.

 

[baseballfanatic2]

SLD-80-56

http://www.farnell.com/datasheets/2860313.pdf

And a BIG correction.. at 2000mA you are restricted to about 40V (39.2 to be more precise)


MY mistake.. need to honor the 78.4 watt rating.
see spec sheet

So 12 in series 2 parallel strings
12 x 3.2V= 38.4 x 2A x 1/2(current split) x 2 series strings =76.8W
OR 24 in series @ 1A
24 x 3.2V x 1A = 76.8

Best practice usually suggests leaving 10% as a buffer so really
70.56 W is the goal..

11 or 22 diodes.. 70.4W
whatever diode you use need to know approx V(f) at the current you want to use..

At 2A you are limited to say 39.2/ 3.6V (guess for now) 10 diodes in series.
10 x 3.6 x 2 = 72W.. ignoring the 10% fudge.

LEDs get more efficient at lower currents for the most part. Some by a little, some by a lot so "underdriving" but more diodes at a lower drive current but same wattage is a gain... but it gets to be a matter of cost at times.

Since I firmly believe in passive cooling I'd never max out the diode BUT it's a philosophy.. no more, no less.
1/2 max is a sort of rule of thumb for me, broken here and there.

Hope that's all correct.. a bit worn out atm.

Thank you so much! Always willing to help! I will use this info. I discovered this driver, as it’s thin and smaller than most. I don’t like the bulky power blocks they sell. Really bad. Always looking for thin and skinny. If you know any at the top of your head, I’d love to know. This is the smallest one in length I’ve seen for how skinny it is.