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3V LED selection for commercial product

Started by rrzayev 3 months ago5 replieslatest reply 3 months ago64 views

We are using WS2812B model LED on our device prototype. It is very simple to use, and works good for our application. 

Now we are designing the commercial version, and I am not sure if we should keep the same LED. There are two reasons:

1) The datasheet of LED mentions 3.7 - 5.3V power supply requirement. Our device is Li-Ion battery powered(3-4.2V), and there will be scenarios when the supply to the LED will be below 3.7V. Hence, the device selection seems inappropriate to me. Even though LED seems to work ok in our device, I have seen it to lose its color properties in other battery powered application, once the battery reached lower capacities. The colors lose their tones, or may completely show invalid colors. 

2) The website of the company doesn't seem very reliable to me, same goes for the datasheet. 

Since it is quite popular device, I thought perhaps some of you may have gone through similar process. 

I wanted to ask you:

1) Have any of you used it in Li-Ion powered commercial device? 

2) Is there any other LED that you would recommend with similar functionality but which is powered from 3V? Communication protocol is not that important, we can do whatever the LED requires. 

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Reply by CustomSargeApril 29, 2021

Howdy, in no particular order:

Requesting advice when we have to look up the device referred to ain't a good start.

A fully integrated RGB LED controller that includes serial port access seems expensive. Compare it to a DAC (or direct PWM) driving a transistor array (roll your own). Or one of the Many multi-channel integrated LED drivers not having such low volt limit ($ well spent). SPI or I2C devices are readily available, but there's no mention of control cable length.

You don't state if a uC (microcontroller) is part of this - a complete gamechanger.

Depending on required battery op time, I'd beef up my Li unit - the 18650 is my go to part in handheld stuff I've built.

Not trying to be overcritical, but engineers Hate vague.  G.H  <<<)))

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Reply by rrzayevApril 30, 2021

Hello, 

Thank you for your reply. 

To clarify, we are using just a single LED, the question is not about a LED strip. The LED is connected to a microcontroller (nRF52). Purpose of LED is to indicate the device state, and it should be bright enough. I have attached few photos for your reference. Photos are from different project using the same LED, but it shows what kind of LED indication we are looking for. 

img_4466_17974.jpg

img_4465_6232.jpg

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Reply by MichaelKellettApril 30, 2021

We don't know your plans for this product but if you intend to manufacture a reliable device over a period of years you should think very carefully before using an single source mass market consumer part from the far east unless you have good contacts with the source.

Using the colour of an LED to indicate status of a device will require that you be very careful not to exclude colour blind people from using it.

My first base would be - use three red LEDs.

Next, if you must have colour, use a multicolour LED froma reputable source and do a bit more work in the micro.

Finally, if you mean to sell a product never use parts run out of spec unless you are willing to test 100%, really understand why they are specced as they are, and you can live with buying a batch of bits that don't work.

To answer your question directly, if I were you I would not use that part.


MK


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Reply by rrzayevApril 30, 2021

Thank you very much. I guess I will keep looking for an alternative LED.

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Reply by jkvasanMay 11, 2021

Hi

You could use a booster such as LM2733 (TI part) or MT3608(Chinese part) to boost the voltage to 3.7 V. the beauty of these devices is , if you shut them down using shutdown pin, the input voltage is directly connected to the output. This means, you need to enable the booster only when the battery voltage is lower than the desired levels. This will work as it has worked for me in another similar application.