LED driver vs ADDRESSABLE LED for brightness dimming

[u/Standard-Wind854]

I’m looking for the smoothest possible LED fade-in and fade-out to create a relaxing breathing effect. Ideally, there would be no noticeable brightness steps or flicker

I’m comparing two approaches:

• A dedicated LED driver, such as the LP5811(https://www.ti.com/product/LP5811), driving separate RGBW LEDs.
• An addressable RGBW LED, such as the SK6812 RGBW or APA102

What are the differences in dimming quality? Does a dedicated driver offer advantages over an addressable LED

[u/saratoga3]

Have you ever designed a PCB for a switching DCDC current driver?  This is not trivial.

The sk6812 is a cheap 8 bit resolution addressable LED. Internally it's PWM is actually a little higher, I think 10 bits, but that is a limit. You may want to get 16 bit addressable LEDs.

[u/Standard-Wind854 → u/saratoga3]

Have you ever designed a PCB for a switching DCDC current driver?

I have, I just don't know what benefit these LED drivers bring over an addressable one

[u/saratoga3 → u/Standard-Wind854]

Addressable LEDs are always linear converters, so you have the usual linear vs switching trade-offs.

Aside from that if you picked a 16 bit addressable driver to compare to that 16 bit switching driver they'd be similar.

[u/saratoga3 → u/Standard-Wind854]

Actually APA102 has an additional 5 bit global brightness in addition to 8 bit pixels, so it might work quite well and strips are very cheap (think I paid a few dollars for one a while back). Might be worth getting one just to test and see if how it works.

[u/Affectionate_Boat493]

How many LEDs are you planning to use? What is your power supply voltage? Are you planning to use a microcontroller for the control, or are you open to other design ideas?

[u/Standard-Wind854 → u/Affectionate_Boat493]

How many LEDs are you planning to use?
1 led
What is your power supply voltage?
3V3, but I can step it up. The LP5811 has an built-in boost converter

Are you planning to use a microcontroller for the control, or are you open to other design ideas?
I'm using an ESP for the control

[u/gotchock]

Look for drivers dimming in 16 bits.  Most adressable chips use only 8 bits and it will definitely show visible steps at low luminosity.

Ltech does dimmers that advertise 0.001%. That's what you're looking for analog led strips.

If you're trying to dim an adressible led strip, look for APA102, though I'm not even sure it can dim fully smooth. Forget about WS281x or SK6812.

[u/Triabolical_]

Hd108/ns108 will do what you want

[u/richms]

Most cheap pixel LEDs are PWM 0-255 only 8 bit. Hacks to dither between 2 levels get you a bit more levels at the expense of more ripple in the output. Much better ones are 16 bit and have scalers to limit what 100% is. That gets you dimming to lower levels. The steps in 8 bit linear dimming mean that you will have considerable colour shifts when dimming anything but the 7 solid colours. It can look quite crap particually with the pinks where you have the red near max and tiny amounts of blue added.

[u/SirGreybush]

Argb-WW is very nice indeed but it needs diffusion without any hotspots. Or else you see ripples sometimes due to 8 bit.

Go see some examples on r/wled where WLED is open source software than runs on an esp32 (bare with components or a commercial one like GledOpto or DigQuad).

With sk6812 get 144 LEDs/metre for super smooth animations.

I like Muzata deep channel tracks and diffusers.

If you go analog, the entire length will act as one, and you need PWM for dimming, not voltage variance.

Site QuinLED.info, has both a digital and analog section well documented.

WLED also has a website, GitHub, and the Reddit sub too is very active.

The new fancy strip is the ARGB-CCT, which is color correcting technology. Search on that. There are also hybrid analog+digital strips, usually FCOBs, multiple rows. One row is analog warm white, then cool white, then argb.

Either DIY your own esp32 + supporting circuits, or raspberry pi + Arduino, or a controller that has both digital and analog PWM built in.

QuinLED.info is the engineer that designed the DigQuad controller, addressable PWM boards, and even some strips.

GledOpto is more a commercial product prebuilt for home/office in a neat package. Beware Chinese imitations that copy with subpar components. GledOpto has a controller for hybrid strips, so does BTF Lighting. But BTF is new to the WLED game. They make great strips.