IRF630 compatibility with Arduino

Dear All,

I'm planning to use arduino to control the current flow for 12v 5-6A using the IRf630 n channel transistor. Will this work out? If no, please explain and advise. :smiley:

Im using filtered PWM from the arduino to control it btw.

Here is the data sheet. Note that Rds(on) is specified at Vgs =10V. That means that the MOSFET will not be fully turned on with 5V so is not a logic level part. Look for a part with the Rds(on) specified at Vgs = 5V or less.

Im using filtered PWM from the arduino to control it

What does that mean? The PWM signal is filtered before going to the gate?

groundFungus:
Here is the data sheet. Note that Rds(on) is specified at Vgs =10V. That means that the MOSFET will not be fully turned on with 5V so is not a logic level part. Look for a part with the Rds(on) specified at Vgs = 5V or less.
What does that mean? The PWM signal is filtered before going to the gate?

Yes the PWM is filtered before going to the gate.
So does that means it requires 10v to fully power on the mosfet?

kingofdeath20:
Yes the PWM is filtered before going to the gate.
So does that means it requires 10v to fully power on the mosfet?

It means it is like a water tap or air tap, with tube or pipe air-hose....... needed to drive something ... a device of some sort.

It requires a certain level of input quantity in order to get a device to do some desired thing. Not high enough input level..... could result in weak operation, or behaviour that we weren't looking to get.

For the case of the mosfet, the level of applied gate-source voltage needs to make the resistance between drain and source small enough ...... to make the path between drain and source a good electrically conductive path.

If the applied voltage is too weak (when we want to 'turn on' the device), and if you don't get a good low resistance path forming through where we want it, then the device isn't going to do what is desired.

So if your arduino pin puts out a maximum of 5V DC, and your particular transistor requires around 10V DC to do its job properly, then you could expect whatever you want to do is not going to work, or not going to work reliably.

This is where a 'logic level mosfet' could do the job for you. So look up 'logic level mosfet', and get some suitable ones --- eg IRL540 and other varieties.

Southpark:
It means it is like a water tap or air tap, with tube or pipe air-hose....... needed to drive something ... a device of some sort.

It requires a certain level of input quantity in order to get a device to do some desired thing. Not high enough input level..... could result in weak operation, or behaviour that we weren't looking to get.

For the case of the mosfet, the level of applied gate-source voltage makes the resistance between drain and source small enough ...... to make the path between drain and source a good electrically conductive path.

If the applied voltage is too weak (when we want to 'turn on' the device), and if you don't get a good low resistance path forming through where we want it, then the device isn't going to do what is desired.

So if your arduino pin puts out a maximum of 5V DC, and your particular transistor requires around 10V DC to do its job properly, then you could expect whatever you want to do is not going to work, or not going to work reliably.

This is where a 'logic level mosfet' could do the job for you. So look up 'logic level mosfet', and get some suitable ones --- eg IRL540 and other varieties.

Thanks for the help!. I think i will be getting the IRL540 as the stock is available. if the amperage is 28A, will it be fine?

kingofdeath20:
if the amperage is 28A, will it be fine?

With watercooling, maybe.
This number comes from the first page of the datasheet.
The part of a datasheet that you should largely ignore.
Leo..

Hi,
Why are you filtering the PWM before it gets to the gate of the MOSFET?

What are you controlling the current flow through?

What is the application?

Thanks.. Tom.. :slight_smile:

TomGeorge:
Hi,
Why are you filtering the PWM before it gets to the gate of the MOSFET?

What are you controlling the current flow through?

What is the application?

Thanks.. Tom.. :slight_smile:

It's for peltier cooling purposes. As peltier will be dmged if using PWM.

You need to filter after the MOSFET, not before!

When you filter your PWM you basically create a 0-5V DAC, so what you will have on your gate is an analog signal, not a digital signal. For example for a 50% PWM signal you would have 2.5V on the gate.

Best case it will not work as you expect, worst case you will destroy the MOSFET.

Depending on your MOSFET it might not turn on at all or it might turn on partially and you would have a voltage drop from drain to source, possibly dissipating tens of watts in your MOSFET which will make it very hot unless you have a very big heat sink on it!

Why not just regulate the peltier element like a thermostat?
If temperature <= SetPoint - 0.5°; turn ON peltier
If temperature >= SetPoint + 0.5°; turn OFF peltier
This would only switch the peltier maybe a few times a minute, not thousands of times per second.
Also I’m sure the peltier will be more effective at 100% load instead of variable load.

GeronimoDK:
You need to filter after the MOSFET, not before!

When you filter your PWM you basically create a 0-5V DAC, so what you will have on your gate is an analog signal, not a digital signal. For example for a 50% PWM signal you would have 2.5V on the gate.

Best case it will not work as you expect, worst case you will destroy the MOSFET.

Depending on your MOSFET it might not turn on at all or it might turn on partially and you would have a voltage drop from drain to source, possibly dissipating tens of watts in your MOSFET which will make it very hot unless you have a very big heat sink on it!

Why not just regulate the peltier element like a thermostat?
If temperature <= SetPoint - 0.5°; turn ON peltier
If temperature >= SetPoint + 0.5°; turn OFF peltier
This would only switch the peltier maybe a few times a minute, not thousands of times per second.
Also I’m sure the peltier will be more effective at 100% load instead of variable load.

So i guess that putting the passive filter at the drain will be a better solution as turning on and off the peltier using PWM will be harmful to the device.