Designing my own rgb led pcb board

Discussion in 'The Projects Forum' started by Logan220, Oct 24, 2014.

  1. Logan220

    Thread Starter New Member

    Oct 22, 2014
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    Hello all, I need help, I'm not sure how to wire up my ring led in a series of a curved led strip, I'm using a cad program to design my own PCI board but I'm not sure how my smd 5050 LEDs wire up. Ik for every three LEDs I need a 22ohm resistor because my LEDs max power is 3.6 volts. I bought a rgb controller and it has four pins. One fire red green blue and positive. But I'm not sure exactly how to design my board. Like idk what connections to wire up. I'm new here so I'm not real fimilar with how to these LEDs need to be wired with the PCB board. If anyone knows how or has a disgram or any advice. Throw it my way... Thanks you
     
  2. Logan220

    Thread Starter New Member

    Oct 22, 2014
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    Wow, sorry about all the typos. I didn't proof read it after I typed it!
     
  3. adam555

    Active Member

    Aug 17, 2013
    858
    39
    You need to look up the wiring for that particular LED on its datasheet. Also need to know the current, because I guess the 3,6v is the drop down voltage of the LED and the resistors depends on the supply voltage.
     
  4. Logan220

    Thread Starter New Member

    Oct 22, 2014
    6
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    And that is the voltage, I'm using a 12v battery. So for every 3 LEDs I'm using a 22 ohm resistor, but idk how to make a pcb board. So my real question is. How do I design a pcb board for a curved rgb led ring going to a rgb controller with 4 pins. And using my 22 ohm resistors. I need help because I have no idea what goes to what and I really just need to figure out how to lay it out. If anyone can help, thanks
     
  5. Logan220

    Thread Starter New Member

    Oct 22, 2014
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    Okay so I just found this and feel silly for not understand how the rgb LEDs work and that the copper clad runs through in a straight line. Now what I don't understand is why there are three resistors all on different lines, correct me if I'm wrong but for my application shouldn't all three lines running rgb go to one resistor or do I need three resistors one for each color?
     
  6. MrChips

    Moderator

    Oct 2, 2009
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    Three resistors are needed because the voltage to each LED is different.
     
  7. Logan220

    Thread Starter New Member

    Oct 22, 2014
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    Okay thanks! One more question then I think I have this all figured out. The positive line runs straight through but to me I don't see that it touches anything so how does it supply positive current to the LEDs?
     
  8. MrChips

    Moderator

    Oct 2, 2009
    12,447
    3,363
    Presumably this is to allow you to connect the power source from one end of the strip only. The power line can be used as either positive source or return depending on which end of the strip you short out. You will need to short one end of the strip.

    Edit: I can see the RGB at D1 is shorted. I cannot tell if this is the anode or cathode.
     
    Last edited: Oct 26, 2014
  9. Robartes

    Member

    Oct 1, 2014
    57
    13
    There are three resistors (one for each color) to align the brightness of the individual color LEDs. Each color LED's brightness depends on the current through it in a way different from the two other colors (usually, red needs a lot less current for the same brightness than the two other ones), so slightly different resistor values are needed to have the LEDs appear at the same brightness (given the same PWM duty cycle, of course).

    You can see this for yourself by hooking up the LED string to a variable voltage supply and turning it down gradually -- the red LED should be the last to extinguish.
     
  10. Robartes

    Member

    Oct 1, 2014
    57
    13
    I think you will find that next to each LED, the anode strip will have a 'pseudopod' (for lack of a better word) extending under it to provide it with the +12V. If this is like many other 12V LED strips out there, each LED is connected to all four lines, and you can cut the strip on any three LED boundary (to get all the resistors) without having to short anything at the other end.
     
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