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Topic: circuit for switching high current mosphet? (Read 307 times) previous topic - next topic

jonisonvespa

Sep 03, 2019, 12:41 pm Last Edit: Sep 03, 2019, 12:49 pm by jonisonvespa
hi im looking for a simple circuit for switching a high current mosphet there are just so many out there,
can someone please reccomend me one thanks want to use it as a switch to turn on off a motor

this is the mosphet i have, here

thanks https://www.infineon.com/dgdl/irfs7530-7ppbf.pdf?fileId=5546d462533600a40153563a9d1e21d8

TomGeorge

Hi,
Just as important.
What are you switching?
Can you connect the gnd of the controller to the gnd of the circuit you are switching or do they need to be isolated from each other?
What model Arduino are you going to use?

Thanks.. Tom.. :)
Everything runs on smoke, let the smoke out, it stops running....

jonisonvespa

#2
Sep 03, 2019, 04:09 pm Last Edit: Sep 03, 2019, 04:11 pm by jonisonvespa
hi tom
im just going to use a simple push switch, i want to switch high side 42v, and its a dc motor to 80 amps
i know hot to switch a low voltage mosphet but a high current one i dont
thnaks

jremington

Quote
i want to switch high side 42v
With an N-channel MOSFET? Why?

jonisonvespa

#4
Sep 03, 2019, 04:47 pm Last Edit: Sep 03, 2019, 04:48 pm by jonisonvespa
or low side? dont want to use a contactor or relay as it needs to be in a smsll space

jremington

Do use it as a low side switch, and provide excellent heat sinking for the MOSFET.

larryd

No technical PMs.
If you are asked a question, please respond with an answer.
If you are asked for more information, please supply it.
If you need clarification, ask for help.

MarkT

#7
Sep 03, 2019, 06:44 pm Last Edit: Sep 03, 2019, 06:44 pm by MarkT
Use a MOSFET gate driver chip to drive a MOSFET gate, the clue is in the name.  There are 1000's available.

The MIC4422 is a low side driver available in DIP and SMT, capable of several amps if you need it.  Use 10µF ceramic decoupling on the driver, which needs to be powered from 6 to 12V given the specs of that MOSFET.

If you want to switch high-side you'll need a more specialized gate driver with a charge-pump.

60V MOSFET with 42V load is a bit close to the edge.   

Remember switching an inductive load requires a free-wheel diode with a pulse current rating for the full load current.

Bit worried by choice of a surface mount MOSFET - you'll need an aluminium cored PCB to heatsink that.
Screw terminal package might be more appropriate (ISO-TOP for instance).
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

jonisonvespa


wvmarle

Use 10µF ceramic decoupling on the driver,
That's some really serious decoupling :-) But unless OP wants to use PWM on this motor, is a gate driver really needed? Or is it mostly to be able to use 12V easily for the gate?

For packing agreed SMD doesn't sound appropriate for this kind of loads, too hard to get the heat out of. The MOSFET linked to lists 1.4mΩ on resistance, which is really good, but at 80A it still dissipates almost 9W. I'm sure it can be done or the parts wouldn't be made, a larger THT package that can be screwed onto a big heat sink makes a lot more sense. I know you want to place it in a small space but somehow you have to deal with the heat.

Also curious as to what kind of flyback diode such a motor would require!
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

vaj4088

A PCB technology that is good at moving heat is needed, and/or lots of moving cool air.

The rule of thumb for a diode is that it should have at least the voltage rating and current rating of whatever is being supplied to the motor when the motor is being driven.

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