I am currently designing a Circuit that is similar to typical WS2812B ARGB strips but seperatet into modules.
In the offical datasheet, there is no mention of using capacitors as noise protection, but in close to all similar models there is one (104, .1uF) for each lamp.
As I am not that experienced with electrical circuit, my questions are:
- Is a Capacitor neccessary?
- If so, what type?
- Could I use one big Capacitor instead of the multiple single ones for each lamp?
.
For Power distribution, there will be 18 WS2812B Leds on each module and 6 White LEDs (datasheet)
- Would it be better to run a higher Voltage line to each module and the seperate the needed Voltages of it?
- Or could I connect the power of all of them in one Line?
- How many modules could I connect for each Voltage Level of the Main line if I run one?
You are welcome to point out bad components or mistakes I made.
This is the current circuit:
Best Answer
Look closely at the "LED"s.
Yours may look different, I don't even know if this is a WS2812B. But notice, there is a minuscule capacitor inside! In this case the high frequency decoupling job is already done much closer to the chip than you could ever do by adding more ceramic caps on the board.
If your LEDs don't have a cap, then add one. You can add one anyway, component footprints are pretty much free.
Personally I'd add an electrolytic cap on each module, maybe on the back, if there is enough space. Largest capacitance in 6.3V that will fit into both the available width and ten cents, something like 470µF.
Datasheet for these LEDs specs Vf max 3.4V and you use a 3V3 power supply, so perhaps some of the LEDs won't light up properly. Better run it from 5V, but efficiency will be a bit low... unless the 3V3 comes from 5V from a linear regulator, in which case the difference will be wasted as heat anyway.