Controlling LEDs at 8kHz

[Jopo]

I have a Teensy 4.1 and I want to control RGBW LEDs at 8kHz for a photography lightbox. I'm thinking I should use LEDs using SK6812 ICs. I'm not experienced so bear with me as I ask some probably over-asked questions:

-Is SK6812 the best IC for this?
-As long as the LEDs and Teensy have a common ground, is there any reason why it wouldn't be okay to power the LEDs with the power supply and not the Teensy?
-Should I add one resistor per LED or one resistor for the whole circuit?
-Can I fully control the LEDs directly with the Teensy? (Individually adressable, at 8kHz PWM)

I'm sure I am the millionth person to ask so thanks for reading

 

[PaulStoffregen]

-Is SK6812 the best IC for this?

Nope. SK6812 internally uses about 1.1 to 1.2 kHz PWM.

-As long as the LEDs and Teensy have a common ground, is there any reason why it wouldn't be okay to power the LEDs with the power supply and not the Teensy?

Yes, separate power for LEDs works fine with common ground.

-Should I add one resistor per LED or one resistor for the whole circuit?

Unless you have a long wire between Teensy and the LEDs, you probably don't need any resistors at all.

-Can I fully control the LEDs directly with the Teensy? (Individually adressable, at 8kHz PWM)

These LEDs use communication at 800 kHz. At that speed, each LED takes 40 us to receive 32 bits (for RGBW color). Either 50 or 300 us is needed between transmissions.

8 kHz is only 125 us. So if your LEDs can work with 50 us idle, that leaves only 75 us. You could only control two SK6812 per data to send 8000 new RGBW updates per second.

Of course, 8 kHz would be pointless because internally the SK6812 updates at approx 1.1 kHz.

 

[Jopo]

Thanks for responding, and good that you did because I guess I'm finding some bad info online. :\
Are there individually addressable LEDs that run at at 8 kHz? And if so, what are they, and how should I control them?

 

[sndsgd]

Depending on the number of LEDs you need, the APA102 might work for you.