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  1. #1
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    WS2812B SMD RGB LED on 3.3V?

    I was impressed by the Chinese RGB diode with the controller WS2812B
    I would like to use it as a signal LED to the MCU.
    According to the datasheet requires a supply voltage of +3.5V to 5.3V
    Which is not very good for MCU 3.3V.
    Do you have any experience with it, how well / wrong diode works at 3.3V?
    Yes, the blue diode will be less intense, but it would not matter, if blue ligth and driver in LED works on 3.3V.

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    Re: WS2812B SMD RGB LED on 3.3V?

    Hi,

    Even if a lot of people say that they have the experience that it works on 3.3V...
    function simply is not guaranteed
    * it may refuse to work after time
    * it may refuse to work at different temperatures
    * one batch may work, the other batch not

    And for sure your 3.3V power supply will have tolerance and drift, too.

    *********
    Most 3.3V microcontrollers will work up to 3.6V.
    So the safe way (if yo don´t want to replace any part) to use a 3.55V (nominal) power supply.
    Thus you have symmetric +/-50mV of margin. Not much, but a margin.
    Many power supply have adjustable output voltage.

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.



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  3. #3
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    Re: WS2812B SMD RGB LED on 3.3V?

    Most 3.3V microcontrollers will work up to 3.6V.
    Yes but
    - 3,5V need Adj LDO and these are two extra resistors
    - I worsk with MCU STM32 and unfortunately, for most MCUs, ST did not output a voltage reference input and Vda is VRef too and change Vref will affect to ADC
    - an increase in voltage from 3.3 to 3.5 is noticeable by increasing the consumption and warming up of the STM

    in short, it comes to me as much annoyance and little profit.

    If use 5V is her problem with 3.3V logic becouse 0,7*5=3,5 and not 3,3V. i.e 5V and power WS28712B over diode on 4,3 , but this is complicated because need 5V LDO for one signal diode
    I try 3.3V on we will see



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