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Topic: ws2812b power with 3.3V (Read 320 times) previous topic - next topic

uzer123

i use a ws2812b ledstrip and power it with 5V..but the data signal comes from an esp32 (3.3v)..it works fine.
but i would like to know if i can also power the ws2812b ledstrip with 3.3V (its more convenient for my battery powered project). will it work and be safe long term? (datasheet says 3.5-5.3V power supply)

PaulRB

Probably not. The red LEDs will work ok. The green will probably also work, but the blue probably will not work. As the batteries discharge and the voltage drops, soon the green will also stop working.

What batteries are you using?

You must not power the strip from the 3.3V regulator output of the esp32 board, you might burn it, or it will shut  down because of overheating.


uzer123

color is not super important for me.. also, i dont plan to blink more than 1 maybe 2 leds at the same time..
i use 18650 batteries..

no, i am not powering the ledstrip from the esp32, i have an external regulator that i want to power both esp32 (straight to 3.3V pin) and the ledstrip..
not powering the ledstrip FROM esp32..

srnet

#3
Jun 10, 2020, 07:05 pm Last Edit: Jun 10, 2020, 07:06 pm by srnet
i use a ws2812b ledstrip and power it with 5V..but the data signal comes from an esp32 (3.3v)..it works fine.
but i would like to know if i can also power the ws2812b ledstrip with 3.3V (its more convenient for my battery powered project). will it work and be safe long term? (datasheet says 3.5-5.3V power supply)
Depends how lucky you feel and how reliable you want the application.

The controller is outside spec already at 3.3V, so maybe the whole thing will stop working at some point.

The controller at the end of the strip would be even further outside spec.

Try it and see.
No PMs please, they dont get answered.

PaulRB

You could try powering the strip direct from the batteries, no regulator, and the esp powered from the batteries to its 5V/Vin pin, using its on-board regulator. If it works ok with the battery fully charged (~4.2V) it should work until the blue LEDs stop working.

uzer123

hm...thats a good partial solution..BUT the ledstrip is crucial for my project, so i have to be sure that the ledstrip is working as long as esp32 works (btw i use dont prefer 5V pin because the onboard regulator is very hungry..
i plan to use mcp1700 which is using much lower power.
So, i guess i have to try and see what 3.3V can do..
---
blue is supposed to need lower voltage than the other?

PaulRB

Red needs lowest voltage, blue needs highest.

Mcp1700/1702 is a good choice.

What esp32 board are you using and what model of "hungry" regulator is onboard? I would like to know that so I don't buy one by accident. I use Wemos mini (esp8266), which has a good low dropout regulator.

For reliable operation of the LEDs, you should consider a 5V buck converter. But then you may also need a level shifter for the data signal. Use 74hc14 or 74hct14 for this, not one of those i2c level shifter modules.

uzer123

Quote
The controller is outside spec already at 3.3V, so maybe the whole thing will stop working at some point.
why? esp32 can work with 3.3V so you bypass onboard regulator also (as far as i know)

this is what i use.

[qote] you should consider a 5V buck converter. But then you may also need a level shifter for the data signal. [/quote]
 do you suggest any low power 5V buck converter? Level shifter looks, is not in need..
i have used two different projects and ledstrip works fine without one..(i just added a resistor to data pin)


PaulRB

do you suggest any low power 5V buck converter? Level shifter looks, is not in need..
I do not have a recommendation for you, sorry. Maybe you will not need a level converter, if you are lucky. Let us know how it works out.

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