MOSFET wiring

Hello, I'm making this post because I have two questions about this scheme :slight_smile:

I would like to use this schematic to power Leds in series with a 12V battery with mosfets (arduino uno - pin 5V)

I would first like to know if you think it is necessary that I integrate a Schottky diode like on this schematic (D1) for the use I plan to make of the MOSFET.

Also, I would like to know if it would be better to connect the GND of the 5V pin to the GND of the battery (battery, which, at the same time, also powers the arduino Uno) or to the GND of the arduino. From what I understand, it is by definition the same GND since the GND of the arduino is necessarily linked to the GND of the battery, through a voltage regulator, but I would still have liked to have your opinion to be sure I'm not talking nonsense.

Thank you

The diode is used when the load is inductive.

In a cct. like this Arduino GND would be connected to the 12v GND.

MOSFET would be a logic level type.

How many strings of LEDs, how much current?
You might be able to just a TPIC6B595, which is a high current/high voltage shift register with MOSFET outputs.

Your circuit will work. All grounds get connected together. I would suggest using an avalanche rated MOSFET, not knowing the wiring you will be using. The pull down resistor is in the proper place. I would prefer something in the 50 Ohm range but 150 will work. Be sure to connect the MOSFET grounds (drain) to the power supply not the Arduino, the current flowing through the Arduino can cause problems. Pick a MOSFET with a relative low RDSon, it will save you from using heat sinks. STP36NF06L is one of many parts available.


Thank you for all your answers!

Actually, I’ve already mostly built this circuit but I just wanted to be sure of certain things as I designed it some time ago.

So, I used a SL2300 which I assume is well a logic level MOSFET. I used a 220 ohms resistor for R1 and a 10k ohm resistor for R2. Each MOSFET will be assigned to a max of 2 to 4 LEDs in series (so 4.2V to 8.4V at 25 mA).

1912111437_Slkor-SLKORMICRO-Elec-SL2300_C350314.pdf (484 KB)

So, I used a SL2300 which I assume is well a logic level MOSFET.

Don't assume.
Read the datasheet instead.
That datasheet, which is remarkable short, in a way unnervingly short even, does say it's logic level indeed. It's the first MOSFET datasheet that I see with only three pages and not a single chart. But considering you have to ask about it, I seriously wonder why you're picking a part that's only available in SOT23 package.

Can you please post a circuit diagram so we can see what your project is about?

Thanks.. Tom... :slight_smile:

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