Powering a LED strip reliably

[MrFollies]

Just out of interest, I looked at TI Webench for high-efficiency converters with DC input between 8V and 24V, output 4V at 4A, <10mV ripple, using integrated inductor modules.  One of the circuits it suggested is based on TLVM13640, which Mouser sells for 6.59€ in singles.  The other components are two 47µF X7R 6.3V 10% caps, two 10µF X7R 50V 20% caps, one 1µF X7R 10V 10% cap, one 8.2pF C0G 50V (0.25pF ≃ 3% tolerance) cap, a 14 kΩ resistor, and a pair of resistors of about 40kΩ total as a voltage divider for 1V output; 28.7kΩ and 10kΩ for 3.9V, 30kΩ and 10kΩ for 4.0V, and so on.  It should exceed 90% efficiency for 0.5A-4A current; about 95% at 1.5A-2.5A.  I like these modules, because having the inductor integrated it is easy to keep the loop area small even on a 2-sided board.  Do look at section 11 Layout in the TLVM13640 datasheet, and remember that some voltage will be dropped by the cables and traces between the supply and the LEDs.

Thanks for this info!

[mariush]

You could get yourself some nice high brightness through hole RED leds, which will have a forward voltage of around 1.8v to 2.2v, and make your own matrix led doing the multiplexing by yourself or using drivers

Example of relatively high brightness led : https://www.digikey.com/en/products/detail/w%C3%BCrth-elektronik/151033RS03000/4490003

(you can get cheaper in 5mm, this one is 3mm)

Example of led driver : https://www.digikey.com/en/products/detail/lumissil-microsystems/IS31FL3733B-TQLS4-TR/12675547

It can do a 12 x 16 led matrix (192 leds) , so you could have 8 or 16 rows,  12 or 24 columns for example .. so with 4 of these you can do 8 x 96 matrix.

Or IS31FL3741A  https://www.digikey.com/en/products/detail/lumissil-microsystems/IS31FL3741A-QFLS4-TR/12675545

It can do 9 x 39 = 351 leds , so you can do 9 rows x (up to) 117 columns with 3 of these.

You could power the controller and the led driver chip with 3.3v or 5v, and you can power the actual leds with let's say 3.0v or 3.3v (the above led driver ic needs minimum 2.7v so I'd use as little as 2.8v)


Without led drivers , you could use a mosfet for each row, and use some mosfet based ULN2003F12/ULN2003V12 as switches to connect columns to ground. See https://www.digikey.com/short/j7qcz8zr

To turn on or off the channels, you could use basic shift registers.
So you basically shift in 100 bits or as many vertical columns you have, and then you turn power to the whole row, wait a bit, turn off power, shift new data for the next row, turn on power to next row, repeat, looping through rows.

[tooki]

You could get yourself some nice high brightness through hole RED leds, which will have a forward voltage of around 1.8v to 2.2v, and make your own matrix led doing the multiplexing by yourself or using drivers

Example of relatively high brightness led : https://www.digikey.com/en/products/detail/w%C3%BCrth-elektronik/151033RS03000/4490003
…

No offense, but that entire approach is just… pointless. It makes no sense to spend $35-70 on LEDs, plus PCBs, plus labor, to produce a matrix you could buy for much less than that! Heck, you can get RGB 64x32 matrices (video wall modules) for less than that, and they’re reasonably easy to drive with an Arduino (with reduced color depth), or an ESP32, Teensy, or Raspberry Pi in full color. They also sell monochrome matrices, and of course one can buy matrix displays (8x8 and 5x7 being the usual sizes) in various sizes and colors for next to nothing.

[jonpaul]

Finished fixtures LEDs refl, driver avail $20..200

We use TCI Italy SLIP drivers, 0-10V dimming 100-240C mains seoectable current 100 mA ...500 mA etc.

j

[Nominal Animal]

No offense, but that entire approach is just… pointless.

Is it?

Let's say you construct 11×11 matrix using WorldSemi WS2812B-V5/W 5050 RGB LEDs on one-sided aluminium 88mm × 88mm boards (8mm or 0.315" center-to-center spacing), using JLCPCB; for a total of seven units, or 55×11 display; total 440mm × 88mm or 17.3" × 3.4".  The 605 LEDs cost $46.10, and manufacturing and assembling the boards somewhere around $20 or so.  There is room for 0603 supply bypass capacitors, too.  With shipping, let's round up to a full $100, although $80 is probably closer to the reality.  Maximum current draw of each panel is 4.4A.

JLCPCB has IS31FL3729-QFLS4-TR (C2940549) 15×9 I²C LED matrix controllers for assembly at $0.74 apiece.  It has one address setting pin, which can choose between four different slave addresses, so at most four such modules can be used in one I²C bus.  It does work up to 1 MHz, though.
Let's assume you use Honglitronic HL-AM-2835H421W-S1-08-HR5(R9) 4000K SMD2835 LEDs (C516127) with a 3.2V forward voltage, run at less than maximum current, say 20mA each.  The datasheet indicates the relative intensity scales about linearly, so the luminous flux should be about 7.5lm.  At 5mm×5mm matrix, each 15×9 matrix would be 75mm×45mm, so say 75mm×75mm for each panel.
Let's say you make ten such panels, for a total of 750mm × 45mm display area, 150×9 LED matrix.
The 1350 LEDs would cost $18 at JLCPCB assembly, the ten controller chips $6.60,  the smattering of capacitors and resistors say $5, and manufacturing and assembling the boards (one-sided aluminium if possible wrt. routing!) about $20 or so.  Say $80 or less shipped.
I do believe this would be well suited to run from a 4V, supply; to drive all ten, you either need three I²C buses or use an I²C multiplexer.
Each of the modules should be able to produce a thousand lumens of luminous flux (at 20mA per LED, 2.7A per panel, 11W if run at 4V), so heat produced will limit the actual brightness in practice.  These LEDs also have 120 degree spread, so they're not the best for this purpose, but I was thinking of some kind of a diffuser with inter-LED barriers here.

Thus, I can definitely see a point for creating ones own matrices.  I do not think it is the best choice in this case, but it is a valid one, depending on the needs.

[tooki]

Again, what advantage does that have over just buying a ready-made panel for a few bucks?

[Nominal Animal]

Again, what advantage does that have over just buying a ready-made panel for a few bucks?

You get the exact dimensions, LED density, and LED type (luminosity, beam angle) you want.

I hope you read my final sentence too, where I said it was likely not the best choice in this case, but a valid one depending on the needs.

In my first reply, I outlined the entire scheme, and mentioned that in my opinion, a better solution would be an IPS TFT display (IPS panels having extremely wide viewing angles) or hacked digital picture frame, and the best solution a large enough e-paper display module, being daylight readable, with the 13.3" SPI modules at WaveShare starting at about $150.

[Buriedcode]

Lets maybe wait for a reply from the OP about what exactly he wants before flooding the thread with lots of different ideas based on speculation?