I need the help of someone more competent at deciphering datasheets of obscure components. I am currently building an LED indoor light installation and would like to have hundreds (400-800) of individually addressable LEDs. The most straight forward solution would be to use the common WS2812 RGB LEDs, that however would entail using copper wires as thick as garden hoses to distribute the 5V power. I know there are also 12V LEDs out there, but 24V would be much better. After several weekend nights of research I have finally found a smart LED that might be up to the task and is pretty affordable at the same time, while not drawing incredible amounts of power doing nothing:

IN-PI55TBTPRPGPB from Inolux (Datasheet)

Now the datasheet is fairly readable to me, but I am missing some critical information here. On page 4 there is a property that is named as "R/G/B port pressure - VDS,MAX" and it states 24V. Does that mean I might be able to attach VCC to a 24V rail? The ratings for VCC are not mentioned anywhere. Every piece of advice is appreciated!

  • \$\begingroup\$ I dont think that means what you want. Have you considered localizing a voltage regulator? \$\endgroup\$ – Passerby Mar 20 at 22:31
  • \$\begingroup\$ @Passerby do you mean like a linear regulator at each segment or each LED? Both of these options sound liker they are wasting a lot of energy to me. \$\endgroup\$ – d.oelert Mar 20 at 22:34
  • \$\begingroup\$ @user263983 As stated in the question, I am aware of that component, but it is not what I want, since I would like to use my 24V power supply. \$\endgroup\$ – d.oelert Mar 20 at 22:54
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    \$\begingroup\$ No, you can not supply 24V to 5V chip. And that parameter, you mention, manufacturer should be asked for definition. It may be a bad translation from Chinese. \$\endgroup\$ – user263983 Mar 20 at 23:01
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    \$\begingroup\$ @d.oelert smaller pockets simply mean you do to the buck regulator table of your favorite distributor and buy what they're currently kicking from their stock at a discount. But even when buying a regularly priced buck regulator IC, inductor and external transistor, for a couple hundred LEDs, this does really not drive up project cost all that much. \$\endgroup\$ – mmmm Mar 20 at 23:27

"R/G/B port pressure - VDS,MAX" and it states 24V. {actually 26V}
Does that mean I might be able to attach VCC to a 24V rail?

NO, That is the maximum Vds of the internal FET with open circuit programmed to draw no current or very little , otherwise meltdown.

You must use 4.5 to 5.5V.

Addition info

36mA max per chip x 5V = 180 mW needs ventilation on both sides or a 3 cm^2 copper substrate, so you may as well get the RGB string and cut into sections and use 48V power to distribute to 5.5v dropping to 4.5V at the end using the LM2956HV PCB’s from Banggood or the 24V to 5V 3A regulators $15cdn/10pc each driving 3A/36mA= Say <80 chips.

  • \$\begingroup\$ I like your additional info. What struck me is that one sees such light installations on occasion, but I never recall seeing a wire "as thick as garden hoses" . Of course if you don't want to build anything but the light string .. maybe such complexities are unwanted \$\endgroup\$ – crasic Mar 21 at 3:43
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    \$\begingroup\$ I have seen conductors of solid copper as thick as an elephant trunk in my 1st job. So I injected 100A and chose a 1ft space or so to get 10 mV or something , put in 2 self-tapping screws and called it a Kelvin shunt ! and monitored up to 100kA into a fusion diffusion bonder with around 4V Nom. Water jets for cooling to make nuclear cooling tubes bonded with a Zirconium shim. Although 1/2” copper water pipes make a nice cheap fixture for conducting high power with low voltage. Plus there no skin effect with DC. And if things get really crazy there’s always a water cooling option. \$\endgroup\$ – Tony Stewart EE75 Mar 21 at 4:41

This is a 5V chip, it won't do what you want.

There are 12V "individually" addressable LED strips that are more efficient, BUT to get to 12V the LEDs are clustered in series strings of 3, so you can't control each LED, only each group of 3 LEDs. If this is okay, then go for it.

There are real 12V individually addressable LED strips where the RGB LEDs are wired in series inside the LEd package. So the chip uses only one current source, which means it uses 3x less current as WS2812B. If you choose white light, it is more efficient. However if you use only one color, then it is less efficient. Since you got separate white LEDs, I guess you won't be using the RGBs for white, so this would not work.

Basically you're going to need a lot of 5V current.

Don't use LM2596 modules from aliexpress. They're all counterfeit chips, with garbage high-ESR capacitors that will overheat and die.

If you to a 4mx3m matrix, then you can power the strips from a beefy 4m long power bus in the middle, and each strip will only be 1.5m long.

However for transportation it will be more convenient to split the panel in smaller chunks. Say four rectangles of 1.5x2m. Or even more chunks, maybe 8 rectangles, so it can be transported easily in a car. Put a 5V power supply on each in the center, with an offset so you can stack the rectangles back to back for transportation, and a 5V bus running in the middle of each rectangle, connected to the center of each strip. It's better to power them from the center rather than from one end, since that cuts voltage drop along the strip in half.

This way voltage drop will be quite low in the short half-strips, and maybe you can tweak the pot on the 5V power supply to decrease voltage a bit. Since the LED chips use current sources, they'll still work on a bit less than 5V, and dissipate less heat.

Several lower power 5V supplies could very well be less costly than a big one, and the low power ones won't need fans.

You will also need 24V power supplies for your white LEDs though. But that's much easier, you won't need one per rectangle.


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