Control 12v 6A 80W water pump with arduino pro mini 3.3V

Hello everybody,

i would like to control (on/off) with an arduino pro mini 3.3V a water pump 12v 6A 80W.

  • option 1: I can use a mosfet IRLML2502 but this max is 4A and i don't know any mosfet which work with 3.3V and can handle 6A
  • option 2 : can i use a MOC3041 and a BTA08-600BW or it will not work with 12v ?
  • option 3: any idea ?

Thank you for your help

I assume you do not have a 5vdc supply available ?

If the pump is DC, then a triac like MOC3041 is not appropriate.
With 12 volts, you don't need a logic level mosfet. Choose a P Channel power mosfet and switch it with a NPN transistor. Google for "high side mosfet switch" and look at the images.

raschemmel:
I assume you do not have a 5vdc supply available ?

Yes i have a 5v with a dc-dc buck converter

6v6gt:
If the pump is DC, then a triac like MOC3041 is not appropriate.
With 12 volts, you don't need a logic level mosfet. Choose a P Channel power mosfet and switch it with a NPN transistor. Google for "high side mosfet switch" and look at the images.

like this : https://i.stack.imgur.com/dXOJT.png ? there is nothing more simple ?

there is nothing more simple ?

Yes, use a logic level N-MOSFET as a low side switch. Make sure it is fully on with Vgs = 3V, and capable of 5-10X the pump current.

30A N-channel Logic Level Mosfet

This one has a Gate Threshold Voltage (VGS(th)) of 2.5V

Yes i have a 5v with a dc-dc buck converter

BOB-09118

BOB-09118

Easiest way to deal with this is to get an dcdc ssr

Easiest way to deal with this is to get an dcdc ssr

That probably is the easiest way...(plug & play)

raschemmel:
30A N-channel Logic Level Mosfet

This one has a Gate Threshold Voltage (VGS(th)) of 2.5V

The MOSFET datasheet shows the max threshold voltage for 250uA is 2.5V but looking at Figure 6: Gate Charge Characteristics, the Miller plateau is at about 4V which suggests 3.3V won't be able to fully drive the FET open ?

You got me

If the RDS(on) ohms is quoted only for voltages higher than you are going to drive it at, then you can't make any assumptions about its performance in the unspecified region.

The FQP30N06L data sheet quotes a maximum RDS(on) of 0.045 ohms at 5Volts (and a slightly better one of 0.035 ohms at 10Volts). You could argue that it was not fully turned on at 5 volts but the 0.01 ohms improvement at 10 volts is not very significant.

Wonder how (if) a logic level MOSFET combined with a voltage doubler would work? For ON/OFF and low speed switching only.
fetVdblr.png

fetVdblr.png

@6v6gt,

If the RDS(on) ohms is quoted only for voltages higher than you are going to drive it at, then you can't make any assumptions about its performance in the unspecified region.

The FQP30N06L data sheet quotes a maximum RDS(on) of 0.045 ohms at 5Volts (and a slightly better one of 0.035 ohms at 10Volts). You could argue that it was not fully turned on at 5 volts but the 0.01 ohms improvement at 10 volts is not very significant.

Good observation,
I'll remember that for next time.
Thank you,
+1

@snyfir,

The MOSFET datasheet shows the max threshold voltage for 250uA is 2.5V but looking at Figure 6: Gate Charge Characteristics, the Miller plateau is at about 4V which suggests 3.3V won't be able to fully drive the FET open ?

Good observation,
Thank you,
+1

JCA34F,

Wonder how (if) a logic level MOSFET combined with a voltage doubler would work? For ON/OFF and low speed switching only.

+1

6v6gt:
If the RDS(on) ohms is quoted only for voltages higher than you are going to drive it at, then you can't make any assumptions about its performance in the unspecified region.

The FQP30N06L data sheet quotes a maximum RDS(on) of 0.045 ohms at 5Volts (and a slightly better one of 0.035 ohms at 10Volts). You could argue that it was not fully turned on at 5 volts but the 0.01 ohms improvement at 10 volts is not very significant.

It means i can use the FQP30N06L with 3.3V in the gate or i nead to find another mosfet ?

Look at Fig 2 on page 3

Where is the intersection of VGS and ID ?

snyfir:
It means i can use the FQP30N06L with 3.3V in the gate or i nead to find another mosfet ?

The quick answer is no, but someone may be able to suggest a suitable one. Here is the relevant data sheet extract. The absence of a GS rating below 5 volts is important here.

A high power rating, 3.3 volt logic level mosfet is difficult to find.

This is made worse because you are searching for a combination of parameters: a low resistance between drain and source at a low voltage between gate and source with a high current capacity between drain and source. The search tools from Mouser, Farnell etc. don't easily support such compound searches.

It has already been pointed out that with 12 volts, you don't need a logic level mosfet, providing you don't want to switch it directly with a 3.3 volt Arduino pin.

Here from: Constant Innovation in Quality Control - SparkFun Learn but also include the flyback diode and capacitor suggested in post #4. The P channel mosfet does not have to be logic level so you have a much wider choice. Note though that the 100 ohm resistor shown for the base of the transistor is far too low for an Arduino pin and a 1k would be a safer choice.

snyfir:
i would like to control (on/off) with an arduino pro mini 3.3V a water pump 12v 6A 80W.

  • option 1: I can use a mosfet IRLML2502 but this max is 4A and i don't know any mosfet which work with 3.3V and can handle 6A

PMV16XN is rated 6.8A continuous, but you have to take care designing the PCB to have enough copper to deal with the heat produced at this current (RDS, ON about 24 mΩ so 864 mW at 6A, this requires a 4-6 cm2 mounting pad on the PCB!).

Alternative: use two in parallel.

raschemmel:
This one has a Gate Threshold Voltage (VGS(th)) of 2.5V

For switching with 3.3V you're looking for a way lower value, such as the <1.2V of the IRLML2502 or the <0.9V of the PMV16XN.

Thank you for your help.
Maybe i will use a relay, because no mosfet has been found

snyfir:
Thank you for your help.
Maybe i will use a relay, because no mosfet has been found

I guess you mean a relay module. An Aduino pin would not be able to drive a suitable relay without a transistor (or 3.3v logic level mosfet) to help.