View Full Version : Would this work RGB Control

12-09-2011, 05:05 AM
Presuming I only want to control Red Green Blue with as few SSRDC's as possible , would the following diagram work ? Also presuming that I am only drawing 10 - 20 Ma per string


12-09-2011, 05:24 AM
You've basically drawn a circuit for a typical flood light. You would need to have current limiting resistors on each color and each LED "string" path - you can't tie them all together as you have. You didn't indicate the voltage used but with four G or B LEDs, you are looking at around 3.2 x 4 or 12.8V for the LEDs and some drop across the current limiting resistors. If you use a much higher voltage - like 24v, this will leave a fairly large amount of voltage for the current limiting resistor to drop resulting in as much as 160 to 320mW of power (for Red) so you might need large resistors (1/4 or even 1/2W). What voltage are you planning to use - and how many of these per channel are you looking at?

12-09-2011, 05:52 AM
Im thinking 12 v rgb 5050's up to 36 channels per color maybe 48 . Have an idea in mind for a new display item but very channel intensive if I wire it normally

12-09-2011, 12:47 PM
If you want to use 12v then you would have to drop down to 3 LEDs per "string" instead of 4 as you have drawn. As I mentioned above, this is typical for a flood example such as THIS (http://www.doityourselfchristmas.com/wiki/images/2/21/DIYC_Flood_Schematic1.jpg). From that, just add additional sub-strings of LEDs per color path - 48 should be fine since even at maximum current of 20mA, you would be at .96A so a DCSSR (or similar) would work fine. Also - from the schematic, replace the constant current drivers with resistors. There are lots of RGB drivers out there as well with DMX front ends that could be used for this.