Hoping someone can help me out here. I can't seem to find a straight answer anywhere. Hope i'm not asking for too much.
I'm trying to control multiple 100W RGB LED COB's using the PWM pins on an Arduino Mega. Im unsure of how to wire between the Arduino and the LED Chips as well as unsure as to which MOFSETS I would need. I know I need a 3 MOFSETS for each LED (One for Red, One for Blue, One for Green) but don't know what model MOFSETS I need. And if they should be P-Channel or N-Channel. First I thought N-Channel but since the RGB LED's have a common Cathode, then I would need P-Channel, right? And if P-Channel, are there any that can handle the higher voltage (24v and 35v) while using the low PWM voltage coming from the Arduino?
If someone can send me a Fritzing diagram and also let me know what MOFSET I should use and or what resistors I need, it would be greatly appreciated. The Fritzing diagrams are preferred as I am still learning how to read/fully understand electronic schematics.
The plan is as follows:
-The 12v power supply would be connected to 2 DC boosters (One that boosts the 12v to 24v for the Red channel and the other that boosts the 12v to 35V for the Green and Blue channels).
-The higher voltages would then be connected to the source pin on the respective MOFSETs.
-Then I would have the Arduino PWM pins send the PWM signal to the MOFSET Gate allowing the desired voltage to flow to each color pin on the LED COB.
-There will be a total of 3 100w RGB LED COBs controlled by the Arduino and the 12v power source.
So the questions are:
Does this sound correct?
Which MOFSET do I need? (Part number would be awesome!)
Fritzing diagram of wiring. (including wiring of ground wires) and placement of resistors if needed.
You can't drive high-power LEDs from a regular (constant voltage) power supply and a MOSFET. LEDs are driven by a constant-current power supply. (Or a "controlled current" power supply if it's dimmable.) The power needs the ability to provide the necessary voltage and with the correct current the voltage "falls into place".
And, it's a bit silly to use a 12V power supply and a step-up DC-DC converter.
And even if you could make this work, how would you expect to drive 3 100W LEDs with a 150W power supply? Plus, you need more than 24V for the 100W LEDs.
For 3 RGB LEDs you'll need 9 power supplies (or drivers). (You can put single-color LEDs in series and run several from one power supply, but you can't put RGB LEDs in series because there is a common anode or common cathode.)
The industry standard for dimming an LED power supply is 0-10VDC or 10V PWM. So, you may need a "small" 10V power supply and 3 "small" transistors or MOSFETs.
DVDdoug:
You can't drive high-power LEDs from a regular (constant voltage) power supply and a MOSFET. LEDs are driven by a constant-current power supply. (Or a "controlled current" power supply if it's dimmable.) The power needs the ability to provide the necessary voltage and with the correct current the voltage "falls into place".
I was able to power a single color 100W LED COB with the same power supply so Im not sure I understand why the RGB would be any different.
DVDdoug:
And even if you could make this work, how would you expect to drive 3 100W LEDs with a 150W power supply? Plus, you need more than 24V for the 100W LEDs.
The power supply I have is NOT 150W. It is 360 watts. And yes I know they need more than 24v. But the voltage is different for each color. Red requires 24v and the Blue and Green operate from 30-36v each.
DVDdoug:
For 3 RGB LEDs you'll need 9 power supplies (or drivers). (You can put single-color LEDs in series and run several from one power supply, but you can't put RGB LEDs in series because there is a common anode or common cathode.)
As I mentioned, the LEDs I have are common cathode. And needing 3 power supplies for each LED does not sound right.
DVDdoug:
You'll also need to heatsink the LED.
Yes, I am aware of this and already plan on using heatsinks with cooling fans.