Hello there.
My first time, using mosfets. I think I narrowed it down a bit.
prices are the same. I will buy packages, so I will have more than enough.
Energy efficiency plays not a big role, since the pwm control signal is very low if I understood correctly.
If understood correctly: IRLZ44N is for low-signal and it can handle some power.
AO3400 more for low-power stuff.
So my choice was IRLZ44N. Maybe more versatile in future, when buying in 10piece package.
But then I heard someone saying they are NOT truly 3.3V, but will works, mostly.
I also heard other mosfets mentioned, the more I read the more confusing it gets. So many choices.
Also the docs of the systemair are crazy good, even with interactive tools. But nowhere it mentions the frequency of the pwm. that's odd. K Rohrventilatoren · Systemair
Some reddit post categorized the IRLF44N as 5v gate voltage.
But I checked datasheet: It's 1V-2V gate threshold voltage.
No nothing mentioned, only these are related:
|Ventilatorsteuerung Drehzahl|2.467|||
=FanCONTROL RPM.
and 0-10V Signal.
after talking to AI, it recommended IRLB8721, which is a true 3.3V logic mosfet.
Not sure what to take.
Could you give a quick answer please, order closes in 20mins for the day...lol.
Threshold is when the FET is beginning to open, but you need higher voltage to get it "fully on" Every MOSFETs datasheet have diagrams that show when a MOSFET is fully on, and at the different voltages (it's resistance will vary with the voltage, but considered in on state). The higher the Vgs, the lower resistance.
It's RDSon that matters, and at what voltage(s) Vgs is spec'd, in this case 10V and 4.5V.
Also at the top the datasheet it usually mentions it; I got a MOSFET which datasheet says "Ultra Logic level (1.8V rated)", so you can go even lower than 3.3 for it to be considered fully on.
Btw, that IRLB8721 is an ok MOSFET, but consider pick a FET for the purpose. If it will shunt 5A, then IRLB8721 is overkill, even if it can do it. It's like buying a semi truck to drive the kids to school. Also bigger FETs needs more kick to startup, an output pin from an MCU might not be ok with it and burn out.
thanks both of you. They did not send the package yet. But none of you mentioned an alternative?
would the IRLF44N been better then? maybe not true 3.3V but maybe not that hot?
That sounds much better.
Since fire is the last thing I want
They don't have to. PWM isn't as much about frequency but Pulse Width Modulation. Read about it.
Choosing the right MOSFET is a daunting task. I believe most electronic enthusiasts have in the early days been browsing some major electronics distributor, trying to find that perfect MOSFET, that can be used in every possible scenario. There isn't. IRLZ44N is an excellent choice for many applications, but it's a semi truck compared to a car. Not so many buy a semi just to drive their kids to school. It can be done, but it's totally overkill. Consider this one instead: Si3460DDV. It can take really low Vgs, however there are some "drawbacks" depening how you look at it, it's SMD, can do max 20 V and driven with Vgs 4.5 V continuous 7.9 A.
Neither pwm high/low levels. Did you give it a try with direct pwm from Esp32?
I had once a case of similar "0-10V/PWM" controller and it didn't have any problem with 3.3V PWM... Obviously check the controller pwm pin voltage first .
You're right in that it doesn't mention any low voltage for the pwm, but 1) drive a smaller MOSFET from your MCU, 2) take the 10 V 1.1 mA from connection 4 (terminal block) 3) into the MOSFETs drain, and 4) connect source to connection 3. That way you'll drive it with 10 V, which is optimal.
Edit: Most important of all 5) tie the GND from the fan, connection 2, together with ESPs GND!
