I am trying to understand if I can use IRL540N mosfet with my 24v LED strip(with 24v psu) and esp32(working at 3.3v).
The question I have: the mosfet has a VGS Max value of +-16, esp is working at 3.3v and I have 24v for the led strip, making the difference 24-3.3~ 21v. The difference is bigger then the allowed VGS max of 16v.
Is that what VGS max means and am I unable to use this mofset for my project or am I misunderstanding the meaning of VGS max
If I am unable to use this mosfet, what mosfets would you recommend for this type of project ?
I am trying to understand if I can use IRL540N mosfet with my 24v LED strip(with 24v psu) and esp32(working at 3.3v).
The question I have: the mosfet has a VGS Max value of +-16, esp is working at 3.3v and I have 24v for the led strip, making the difference 24-3.3~ 21v. The difference is bigger then the allowed VGS max of 16v.
Is that what VGS max means and am I unable to use this mofset for my project or am I misunderstanding the meaning of VGS max
If I am unable to use this mosfet, what mosfets would you recommend for this type of project ?
Most measurements are relative to the Source (reference point). Vgs is one of the important parameters to pick a FET. It stands for Voltage Gate Source. This is the voltage needed to turn on the MOSFET . It needs to be less then the voltage you are using to turn it on. There is also a +- rating. This states the maximum voltage you can put on the gate (+- 10V for this part). For a N-Channel MOSFET the Vgs needs to be positive, if it is negative it will remain off. If you exceed the +-10 volt rating you will damage it. The next rating will be the MOSFET voltage rating, the IRL540N is rated at 100V (Vishay data sheet). It also gives you a RDSon value, that is the resistance when turned on. You can use that with Ohm's law to calculate the losses (voltage drop). Note this is directly affected by the temperature and the applied Vgs voltage. It also has a Repetitive Avalanche Rated which indicates you can switch inductive loads without a flyback diode. The data sheet will give you the max. You probably did not pick the most inexpensive part but it is a great part for usage with the Arduino's for both 3.3V and 5V. Remember the source is the reference point and must be connected to Arduino and power ground for the arduino to control it. This should get you started, we are here to help you, so have fun!
I am just trying to underatand if this is what VGS(MAX), THE ABSOLUTE MAXIMUM GATE TO SOURCE +- rating means or not, the schematics are irrelevant. But in this case the source would be connected to the ground of 24v psu and gate to the esp32
Correct. This is a standard low side configuration.
If you connected the gate to +24v to switch the mosfet on you would clearly exceed VGS(max) since the source is a 0 volts.
However, you are not doing that. The gate here is only 3.3 volts above the source when the ESP pin is high, so well within spec.
I am kind of a noob on these topics, but can you please explain. The gate is 21v lower then the source, is it not ? Gate at 3.3v and source at 24v, meaning the vgsmax+- is exceeded? What am I not understanding or is this not how its calculated ?
No. You've just said the source is at ground potential (0 volts).
and this is correct for a low side switch. The gate of the mosfet will be a maximum of 3.3 volts above the source because the ESP shares the same ground (doesn't it?!?). The 24 volts of the power supply is irrelevant. It could be 100 volts and that changes nothing for this calculation.
Just to be very clear, the grounds of the 24volt supply and the supply for the ESP must be connected together (somewhere) so these are both effectively at 0 volts.
I see, yes the esp32 and source are connected to the 24V power supply ground and psu ground is connected to the power outlets ground. Thank you for taking the time to explain this to me, it is clear that I have no idea how the ground works lol.
here is a simple picture of what I have, without the "switch input with pulldown resistor" and "potentiometer", I just have the 10k resistors, mosfets,24v PSU, analog RGB/WWW leds, ESP gets it power from USB
