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I've seen a lot of answers referring to track widths but nothing that concentrates on copper planes.

I'm designing a 300mm by 300mm PCB that's 1.6mm thick and using 2oz copper weight. Evenly distributed around the board are 110 APA102 RGB LEDs (similar to WS2812B). Their max current draw is around 60mA. So hypothetically with them all on max the current draw is 6.6A @ 5V.

How can I calculate whether the PCB can handle this, and what the temperature rise will be?

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    \$\begingroup\$ Resistance of copper should be no problem ; getting rid of the heat from the LEDs should be the main issue here. 33W is quite a lot... fortunately it is spread over a very large area, but you must do the thermal management right... \$\endgroup\$
    – bobflux
    Commented Dec 6, 2017 at 13:11
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    \$\begingroup\$ You will have hard time soldering the LEDs as copper will sink the heat. Prepare for cold joints... \$\endgroup\$
    – user76844
    Commented Dec 6, 2017 at 13:21
  • \$\begingroup\$ @GregoryKornblum yes, hot plate or reflow would help! \$\endgroup\$
    – bobflux
    Commented Dec 6, 2017 at 14:27
  • \$\begingroup\$ @GregoryKornblum What if he solder one LED and use that to heat the rest of the board!! \$\endgroup\$
    – pipe
    Commented Dec 6, 2017 at 14:27
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    \$\begingroup\$ I've done a very similar PCB (300x400) 96 LEDs, and since most of the time the LEDs had some color on them (say, R255,G120,B20) instead of full white (255,255,255) temperature and voltage drop were quite ok. I did test them for days at 100% brightness with no ventilation, and temperature rise was ok as well (dont recall the numbers). Final installation had some ventilation though, just to be safe. \$\endgroup\$
    – Wesley Lee
    Commented Dec 6, 2017 at 14:42

2 Answers 2

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Download and install Saturn PCB Toolkit.

It does the calculations for all the things you're looking for.

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At 6.6A and 2 oz copper you only need a trace that 160 mils wide to keep the PCB temperature rise below 10 degrees C. So if your board is mostly planes you will have way more copper than is needed. Additional planes will lower the temperature rise even further.

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