I am still new to Mosfets.

[Lightium]

Can an IRFP250N handle 3 amps on its gate?

 

[Nigel Goodwin]

FET's are voltage controlled devices, they don't take any gate current (of any consequence). Why are you asking about gate current?.

 

[Lightium]

Because in my simulation, the last thing to worry about that I measured was the gate current. I saw that it was about 3.5 amps and that worried me. Still though i am only dissipating about 20 watts.

 

[Lightium]

Thank you.

 

[crutschow]

Because in my simulation, the last thing to worry about that I measured was the gate current. I saw that it was about 3.5 amps

Obviously some sort of simulation error.

 

[danadak]

There are large gate currents if you are driving them with fast Tr and Tf
inputs, due to gate C.

Classic C equation :

Q = C x V
dQ/dT = I = C x dV/dT

Calculations for driving MOSFETs -

https://toshiba.semicon-storage.com/info/docget.jsp?did=59460

http://www.ti.com/lit/slua618

https://www.infineon.com/dgdl/an-937.pdf?fileId=5546d462533600a40153559ea1481181

An example :

Regards, Dana.

 

[Tony Stewart]

for an estimated Ciss of 2500 pF, Rg=4 ohms est. Vgs=12 to get 3.5 Apeak the dV/dt=Vgs/RgC = 12/4*2.5e-9 or 12V/10ns. Then yes it is possible or a period of 10ns.

 

[Papabravo]

Because in my simulation, the last thing to worry about that I measured was the gate current. I saw that it was about 3.5 amps and that worried me. Still though i am only dissipating about 20 watts.

This is an AC current, not a DC current. The gate of a MOSFET is insulted from the other nodes by a layer of silicon dioxide, which is an insulator. Too much voltage would however be a bad-bad thing. The main reason for it is to charge and discharge the gate rapidly.

 

[ChrisP58]

In a simulation, you can easily get 3.5 Amps (or more) into the gate of a mosfet for a few microseconds.

But is you have that much current continuously, then something is wrong.

 

[Lightium]

In a simulation, you can easily get 3.5 Amps (or more) into the gate of a mosfet for a few microseconds.

But is you have that much current continuously, then something is wrong.

Another good thing to know, thank you.

 

[Tony Stewart]

In a simulation, you can easily get 3.5 Amps (or more) into the gate of a mosfet for a few microseconds.

But is you have that much current continuously, then something is wrong.

how do you get microseconds of gate current from Ic=CdV/dt using the parameters in #7 and Lightium ,what time constant did you get?

 

[ChrisP58]

how do you get microseconds of gate current from Ic=CdV/dt using the parameters in #7 and Lightium ,what time constant did you get?

I didn't. The last post that was up when I started my reply was #5. If I had seen your post I wouldn't have replied at all.

My use of 'a few microseconds' was only intended to convey the concept of a very short time.