Parallel mosfets or IGBT from single mosfet driver, if big enough?

Thread Starter

Hamlet

Joined Jun 10, 2015
252
Is this acceptable design practice, or should I use larger Mosfets, larger driver, or use one driver per Mosfet
or IGBT?
 

dl324

Joined Mar 30, 2015
8,956
It depends.

In general, it's better to use a single device. If you cherry pick parts to match characteristics, it's more acceptable. To say with any certainty, we need to know more particulars; specifically, how you plan to use them.
 

crutschow

Joined Mar 14, 2008
23,368
It depends upon the driver current capability, the gate-charge of the MOSFETs, and how fast you need to drive them, to determine whether the MOSFETs can be paralleled with one driver.
In a fast switching application, the difference in characteristics between MOSFETS of the same type are not likely to cause a problem.
 

Thread Starter

Hamlet

Joined Jun 10, 2015
252
Okay, thank you guys for fast reply. I might experiment with each design, even 1+1 will let me run a stack of inexpensive mosfets
for higher current capability. This is all just for my own use, no commercial products.
 

Thread Starter

Hamlet

Joined Jun 10, 2015
252
Again, it depends. If you gave more information, we could give better advice.
I was just asking general advise, like, "hell no, you can't do it!" or "Yeah, works okay, usually."

I'm not trying to obfuscate. I have ideas swimming in my head. Sometimes parallel works, sometimes not.
Like two voltage regulators, paralleled, don't work. Or, one dropping resistor for parallel LEDs, don't work.
I'm sorry I don't have a schematic to share.
 

dl324

Joined Mar 30, 2015
8,956
Sometimes it'll work and sometimes not; it depends.

If you tried to do something like parallel 3 200mA devices to get half an amp, it works until a device fails and the remaining devices start carrying more current. The on resistance won't be the same for all devices, so one will carry more current than the rest. If you derate sufficiently, you could be okay. Cherry picking will also help.

You don't have these issues with a single device.
 

ebp

Joined Feb 8, 2018
2,332
Paralleling MOSFET certainly can be done in switching applications, but care is required. For "ordinary" applications it is probably done much less now than it used to be, simply because of the spectacular FETs that are now available. But the new types have made FETs feasible, if paralleled, where they used to be pretty much out of the question. The following are helpful:

https://www.infineon.com/dgdl/para.pdf?fileId=5546d462533600a401535744b4583f79
https://assets.nexperia.com/documents/application-note/AN11599.pdf

You should be able to find similar info on paralleling IGBTs.
 

Thread Starter

Hamlet

Joined Jun 10, 2015
252
Paralleling MOSFET certainly can be done in switching applications, but care is required. For "ordinary" applications it is probably done much less now than it used to be, simply because of the spectacular FETs that are now available. But the new types have made FETs feasible, if paralleled, where they used to be pretty much out of the question. The following are helpful:

https://www.infineon.com/dgdl/para.pdf?fileId=5546d462533600a401535744b4583f79
https://assets.nexperia.com/documents/application-note/AN11599.pdf

You should be able to find similar info on paralleling IGBTs.
Hey, thank you! I don't want a string of firecrackers going off, do I?
 
Top