I am trying to build a high power RGB LED light. I am looking for 50W-100W range for the LED (all colors combined). 100W RGB LED desn't seem to exist so I am left with 50W, 60W, or 90W options. I would prefer higher wattage single LED module as it's cheaper than multiple lower wattage modules.
There is a suitable 90W LED module. There is no datasheet only this spec:
Voltage: R: 20~22V; G: 32~34V; B: 32~34V; Current: R: 900mA; G: 900mA;
B: 900mA; Product size: 45mm x 51mm; Power: 90W; Wavelength: R:
620~625nm; G: 520~525nm; B: 460~465nm; 10 series and 9 in parallel;
I heard that for LEDs in series/parallel you need some additional components for current sharing etc… Do these LEDs have the required circuitry built-in making them essentially the same as a single LED in respect to powering them? Or do I need a special LED driver to power this module? Reason I am asking is because most LED drivers don't mention any specifics about series/parallel LED but I did recently see an LED driver with PWM control that specifically mentioned it's application was for LED module 1 x 50W multichip(10 Series x 5 Parallel). Does this driver have special circuitry or is it just a suggestion for what it can be used?
What do I need to look for in an LED driver in general other than constant current, min/max voltage range and power rating to be equal or lower to that of the LED. (For the 90" RGB LED, each color would use it's own 30W driver).
Best Answer
If a module has only two terminals, but has some parallel LEDs internally, you can probably assume there's something inside the module to balance the current between each parallel circuit. This is made somewhat easier when all the LEDs are in one module because they can share a heatsink, and thus the temperature of each is likely close, and temperature variations are a big factor in why parallel LEDs will not share current equally. Each LED was also likely manufactured at the same time, so have very similar characteristics, which you can't guarantee when taking discrete LEDs out of a jar. The module may also include some small resistance in each parallel circuit to help balance. Point being: assume the manufacturer has taken care of this, and all you need to worry about is supplying the correct current to the two terminals provided by the module.
Your particular module is really like three modules, one for each color. It looks like there is one common terminal on the bottom, and three separate terminals on the top, one for each color. I can't find a datasheet that specifies if the cathodes or the anodes are common, so you may have to figure it out for yourself. It looks like maybe you can cut the common terminal apart if you want, but again, I see no datasheet, so you might have to experiment for yourself.
There is no special kind of LED driver that can drive parallel LED circuits. If an LED driver's job is to pump electrons, there's no way for it to tell some electrons to go down one circuit while telling others to go another way. The electrons decide which way to go by going whichever way minimizes their potential.
So, what you want to do with this module is power each of the R, G, and B sub-modules with a suitable driver (or if you can find it, one box that actually has three drivers in it). What you don't want to do is try to put the R, G, and B sub-modules in parallel and drive them all together. Since each color has a different forward voltage, this won't even remotely work: the color with the lowest forward voltage (red) will take very nearly all the current and all the power, and possibly be destroyed. At best you just won't get the other colors to light.