Controlling 36v 3 Amp LED with Arduino

Thread Starter

awwwt

Joined Aug 24, 2015
60
Hello,

I am hoping to control (dim, brighten, turn on + off) this DC 31-36V 100W (3A) LED with an Arduino.

The LED is using an AC to DC power supply that gives it the correct amount of power (output 24-36v 3000ma). I am also using a huge heat sink that means that the LED doesn't heat up much at all when in operation.

I have purchased some MOSFET transistors (these ones) to implement with the Arduino. The instructions I will be following can be found here.

My question is whether this will be appropriate to do? - whether it is safe and the correct way of controlling such a high power LED?

Suggestions and alternatives welcome, but it would be good to know if I can go ahead with this route.

Thanks!
 

LesJones

Joined Jan 8, 2017
4,174
The mosfet suggested in the article is more suitable than the one you have chosen. The mosfet in the article has it's rDS(on) value quoted with a gate to source voltage of 5 volts which the Arduino output will provide. The mosfet you have chosen has it's rDS(on) value quoted with a gate to source voltage of 10 volts which the Arduino output will not provide directly. This will mean that with only 5 volts to the gate it will not turn fully on so there will be a larger source to drain voltage when it is conducting which will generate more heat. It will probably work but you may need to provide some heat sinking. A better way would be to use a bipolar transistor and a 10 volt power supply to increase the voltage to the gate. Using a single transistor would invert the signal so you would need to correct for this in the software.

Les.
 

Thread Starter

awwwt

Joined Aug 24, 2015
60
Depends on what you meant by "this"?

It is entirely safe to control high power devices with your Arduino, assuming it is properly designed.
Sorry for not being clearer, I mean whether it's OK to follow the tutorial I mentioned using the components I linked to. But thank you for letting me know it's safe!
 

Thread Starter

awwwt

Joined Aug 24, 2015
60
The mosfet suggested in the article is more suitable than the one you have chosen. The mosfet in the article has it's rDS(on) value quoted with a gate to source voltage of 5 volts which the Arduino output will provide. The mosfet you have chosen has it's rDS(on) value quoted with a gate to source voltage of 10 volts which the Arduino output will not provide directly. This will mean that with only 5 volts to the gate it will not turn fully on so there will be a larger source to drain voltage when it is conducting which will generate more heat. It will probably work but you may need to provide some heat sinking. A better way would be to use a bipolar transistor and a 10 volt power supply to increase the voltage to the gate. Using a single transistor would invert the signal so you would need to correct for this in the software.

Les.
Thank you so much for this, it's really informative and I totally missed the part about the 5 versus 10 volt supply to the mosfet from the Arduino - so thank you for teaching me this. I have got one of the mosfets mentioned in that article so I will try with that. I went for a higher value for this project because of the significant amperage required. If a 30A rated mosfet would be OK, then that's really reassuring.
 
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