Driving 3W RGB Common Anode LED

Thread Starter

PropForge

Joined Mar 5, 2016
16
I have a bunch of these LEDs I got years ago and am inexperienced when it comes to high power LEDs and MOSFETs.

The end goal is control a LED's intensity and color via Arduino, illuminated for short periods of time, essentially a single bright flash.

Attached is a layout I've tossed together using FQP30N06Ls. I'd like a few more eyeballs to check it, especially my resistor values, before I breadboard it and start releasing magic smoke.

3W RGB CA LED DRIVER 001.png
 

Thread Starter

PropForge

Joined Mar 5, 2016
16
Black backgrounds are easier on my eyes.

I was going off other examples I've seen with resistors on the gate, which is why the 220Ohm resistor is there (MOSFETs are a new beast to me). The 10k is so the data pin isn't floating, and the remainder are for the LEDs.
 

dl324

Joined Mar 30, 2015
11,251
Black backgrounds are easier on my eyes.
It's the opposite for the majority. Think about all of the schematics you've seen in datasheets, databooks, and text books. Most will be black foreground on a white background. Some screwballs think using colors is helpful. It isn't unless those colors convey meaningful information.
I was going off other examples I've seen with resistors on the gate, which is why the 220Ohm resistor is there (MOSFETs are a new beast to me). The 10k is so the data pin isn't floating, and the remainder are for the LEDs.
If the outputs from the microcontroller are always driven, the pulldown resistors are unnecessary. The series resistors are to limit gate charging current. The drive capabilities for microcontrollers seem unnecessarily difficult to find. I tried checking ATmega328 and couldn't find it.

Wouldn't have done any good anyway because your schematic doesn't give a part number for the MOSFETs. That's better than showing other meaningless parameters which only tell us that your being too conservative.
 

jpanhalt

Joined Jan 18, 2008
10,082
It's the opposite for the majority. Think about all of the schematics you've seen in datasheets, databooks, and text books. Most will be black foreground on a white background. Some screwballs think using colors is helpful. It isn't unless those colors convey meaningful information.
If the outputs from the microcontroller are always driven, the pulldown resistors are unnecessary. The series resistors are to limit gate charging current. The drive capabilities for microcontrollers seem unnecessarily difficult to find. I tried checking ATmega328 and couldn't find it.

Wouldn't have done any good anyway because your schematic doesn't give a part number for the MOSFETs. That's better than showing other meaningless parameters which only tell us that your being too conservative.
Text mode has been discussed here as well as widely on the Internet. https://www.quora.com/Is-dark-mode-light-text-on-a-dark-background-really-better-for-the-eyes One cannot satisfy everyone. Personally, I prefer black on white, except when routing a PCB, but why keep raising the issue?

Generally, MCU outputs are protected. Nevertheless, the 220 Ω resistors probably do no harm and switching is presumably relatively slow. If for preventing ringing. They will work, but one can usually get by with smaller ones.

The mosfet part number is in post #1. There are 2 versions. TS is using the 35 mΩ version.
 
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