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I'm trying to build an array (100) of WS2812B which are controlled over an Particle Photon, both are powered by a 10A/5V power supply.

Powerwise: 10 WS2812B will be daisy-chained in one row Datawise: All of them will be daisy-chained in one serial row

The whole setup looks something like this: The resistor after enter image description here

I added a capacitor at the power supply to smooth the voltage and a resistor prior to the first WS2812B to protect the data pin.

My question is: Do I really need the individual 100nF capacitors for each LED is the big one at the power supply enough? Or do I even need to add more capacitors, for example in the middle of each daisy chain?

Thanks for the help. I couldn't find to much in the data sheet. But each WS2812B can draw a maximum of 60mA when emitting white at full power.

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Never underestimate the benefits of capacitors. If the lighting was constant intensity any capacitors would be redundant, however if your strobing the LED's or sequencing them, small brief voltage drops would occur in the power feeds.

Even if the WS2812B drives the LED's with constant current 100uF 16vdc electrolytics will remove glitches from the power feeds, especially at the LED's furthest from the power source. If the flashing of the LED's seems to affect other LED's you can use 1,000uF 16vdc capacitors at each LED driver.

Capacitors are cheap for the benefits they offer. Note that the 100nF value you chose are still useful as decoupling for high frequency noise, best if placed at the power pins of the IC.

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  • \$\begingroup\$ Thanks for your answer. The 100nF was taken straight from the datasheet (linked in the question). The LED's within the WS2812B are powered internally by a PWM signal, so there is some 'strobing'. However I was wondering if this effect is small enough so that the main capacitor offers enough smoothing. \$\endgroup\$
    – magu_
    Jul 8 '16 at 5:21
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    \$\begingroup\$ The 100nF caps are for decoupling, not for storage. The WS2812B has a fair amount of circuitry in each one (three LEDs, three PWMs, 24 bit shift register, 24 bit holding register, clock recovery and timing), so decoupling is highly recommended. But to be effective, they need to right at the chip. \$\endgroup\$
    – Mark
    Jul 8 '16 at 7:32
  • \$\begingroup\$ @Mark, got it thanks. So I need both energy storage and decoupling. \$\endgroup\$
    – magu_
    Jul 8 '16 at 14:00
  • \$\begingroup\$ @Mark. Changed paragraph 3 to include 100nF caps, next to IC power pins. \$\endgroup\$
    – user105652
    Jul 8 '16 at 16:49

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