I have similar situation, described here: MeanWell 3-in-1 dimming
So, I need to control MeanWell power by PWM signal from Arduino. I tried to simulate scematics, given as answer in that topic, but it seems doesn't work (in simulator).
Schematics:
Results:
As author of that topic mentioned in one of comments, Vg is about -0.47V, which is not enough to close BSS126. One extreme change is to remove 750k resistor.
Schematics:
Results:
As you can see in this case Vg = -1.4V, which is still less, than required to close BSS126 comletely. I guess because of that maximum Vdim+ is not higher than 5.6V.
I'm quite bad at electronics and already spent a lot of time fighting with this schematics and trying to get 10V if there is no input signal for optocoupler. Can someone advise, what is wrong with this schematics and how to make it work? The goal is to have 0V when there is no input signal and 10V when input signal is 5V.
My MeanWell device is XLG-240-M-AB. When nothing is connected to DIM+ and DIM-, voltage is 14.4V. When I connect resistor 99.7 kOhm, voltage is 9.62V. Which means (if I'm not mistaken) that internal resistor inside MeanWell (please refer to schematics in topic, which I refered to previously) is about 50 kOhm
Best Answer
Figure 1. Input circuitry of some Mean Well LED PSUs. Image source: LEDnique.
This circuit can be driven by a potentiometer, a 0 - 10 V (or 1 - 10 V) source or a PWM signal but the end result is always the same: an analog voltage reaches the IN control pin. See my linked article for more detail.
Connect your opto-isolator's collector to CONTROL+ and the emitter to CONTROL- and you should be able to control the brightness by PWM control of the opto-LED.
simulate this circuit – Schematic created using CircuitLab
Figure 2. Microcontroller interface.
If the GPIO is 100% off the PSU will be 100% on. You can't easily invert that action. (More on this later.)
simulate this circuit
Figure 3. The simplest, no-nonsense method is to use a relay which when de-energised with loss of microcontroller power short-circuits the Mean Well control inputs.