Dimming high power led strips


I want to dim some high power led strips for a custom aquarium light. I have different channels two channels white (warm and cold), red and blue. The white channels have 12V 125w each so around 11A per channel. I want to use a MOSFET to dim the different channels. I tried to find MOSFETs that have the right rating for this job but I am not sure what to look for. I think what I search for is a MOSFET that is rated for 12V 15A permanent. If I look into the datasheet of different MOSFETs I am not really sure what I need to look for. Also, are all MOSFETs usable for dimming with PWM?

Thank you all in advance!


Do not search for anything close to what you want. FET data sheets will show a much larger current that they can realistically handle.

You need to search for a logic level FET, that is one that can be fully turned on with 5V, assuming you are using a 5V Arduino.
This will be a condition of the on resistance rating Ron. Do not bother with the threshold voltage that is the voltage where the FET just starts to turn on.

Then look at what the package can dissipate without a heat sink. To see if you need a heat sink or not.

I think you will find that all power FETs are suitable for driving a string of LEDs.

I have several LED strips pulling about 16 amps at 12V. They are being PWMed by arduinos. Being lazy not wanting to do a lot of hardware work I used BTS7960 bridges to drive them. I connected them as high side driver (lower RDSon on the high side) and the LEDs low side to ground. They work very well and barely get warm. They have been operating for several years. Be sure to use appropriate gauge wire.

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