[SOLVED] Irlz44n with 3.3v signal?

Other Hardware Motors, Mechanics, Power and CNC
22
  • As always with all MOSFETs, we need to make sure Vgs(max) is not exceeded.
    Zeners and voltage dividers can be employed.
23

I assume you have shared grounds...

Using a BJT in front of the fet does nothing if VCC of the gate drive resistor is still 3.3volt.
The fet gets the same drive voltage as directly from the MCU pin.
3.3volt logic is smd territory. You will struggle to find through-hole parts at this voltage.
Leo..

2 Likes
24

But if Vcc is a 3.3V battery as in #1, then Vgs is still the 3.3V as without the BJT?

1 Like
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  • Correct.
    My assumption, Vcc (for the MOSFET load) was > 3v3 but that was/is probably wrong.

A 5A motor at 3V3 needs to be confirmed with the OP ? Please may we get a schematic ?

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See post #7

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See post #3

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but the MOSFET does not. If Vcc = 3.3V ( see post #1) then your circuit does nothing.

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Yeah i they have shared grounds.

30

Im basically trying to drive two coreless motor with the same mosfet. Their stall current total is 4A. To be on the safe side i want the max current to be 5A.

Also the whole circuit is to be powered by two lipos. One small one for the arduino and mosfet while other one(550mah 90c) for the motors.

Btw got another question : If I use a step up 5v to the arduino and give 3.7v for the motors (shared ground) will it work? Is it possible that the motors would try to drive themselves off the arduinos digital pins, burning it in the process?

Thanks everybody.

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This is all you need

image
image939×707 10 KB

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Why?

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I can do basic soldering 0805 and some 3 pin smd components. I have used si2302s before

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Just as a theoretical question.

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Yes it will work.

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Is that for one or two?

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Combined of 2

38

On your OP you stated 3.3V batteries.
Lipo has nominal voltage 3.7V and 4.2V fully charged.
Just to consider, in case your motor is rated something like 3.2V nominal/3.7V max...

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Then if you use 5V for the Arduino, you can use the IRLZ44N MOSFET.

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my mistake sorry

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  • Schematics are the way we communicate to others exactly how our hardware is connected and shows all the components in our circuit.
    When posting on the forums, we need to see your proposed schematic (hand-drawn is fine).