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Driving this dual coloured COB LED?

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LooseJunkHater:
Hello, I want to use 2x potentiometers to control the brightness of the warm white (WW) & cool white (CW) LED’s (image 1; https://www.aliexpress.com/item/4000381180509.html ), but I’m not exactly sure how to drive this LED. I know that I need both CC (constant current) and CV (constant voltage) control for LED's, but since the ground is separated for this LED design, it confuses me. I’m assuming that this style (image 2; https://www.aliexpress.com/item/1005002303002760.html ) of boost converter WON’T work because the ground are commoned together??? Maybe I could get this boost converter to work if they are isolated from each other, but maybe I’m thinking about this the wrong way?

I was thinking of just using a single boost converter and then using a mosfet to limit the current of both the WW and CW LED’s, but this design is obviously nowhere as efficient as simply using two separate boost controllers.

Mosfet to limit current circuit:


What is the intended way/best way of driving an LED like this? Thanks!

ledtester:
It appears that the COB LED looks like this internally:

[attach=1]

The "constant current source" presented in the video operates on the low side - technically it is a constant current "sink". To control both LEDs in the COB you can use two copies of the constant current control like this:

[attach=2]

Each CC control unit would have its own potentiometer.

LooseJunkHater:
Is there any other way to control the LED brightness aside from using the MOSFET for an inefficient constant current control?

Zero999:
What's the supply voltage vs LED forward voltage?

The current needs to be controlled, not the voltage.

The LEDs being common anode doesn't help matters.

LooseJunkHater:

--- Quote from: Zero999 on February 03, 2023, 06:36:29 pm ---What's the supply voltage vs LED forward voltage?

The current needs to be controlled, not the voltage.

The LEDs being common anode doesn't help matters.

--- End quote ---

Voltage: 36-39V, current:600mA+600mA. I understand that the LED needs current control. 

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