MOSFET voltage short

Thread Starter

Haulin

Joined Sep 23, 2022
6
Hi, I have a Bldc motor Controller don't know what went wrong with the controller, the +ive and -ive terminal just shorted. When I opened up the controller all the MOSFETs in one line shows a shortage across all three terminals. What causes all 3 terminals Gate, Drain, and Source to shorten themselves?
I would also like to simulate this type of shortage on a breadboard if anyone has an idea do let me know
 

Thread Starter

Haulin

Joined Sep 23, 2022
6
Welcome to AC!

A wire would simulate a short circuit, but wouldn't add much to your knowledge.
A piece of wire will temporarily shorts the terminals but when I remove that wire shortage will be gone
What I want to simulate is how MOSFETs could be permanently damaged i.e. Showing shortage on all three terminals
 

Thread Starter

Haulin

Joined Sep 23, 2022
6
A piece of wire will temporarily shorts the terminals but when I remove that wire shortage will be gone
What I want to simulate is how MOSFETs could be permanently damaged i.e. Showing shortage on all three terminals
Basically what i want to try is to damage the Mosfet in such a way that all thee terminal of the mosfets gets permanently damaged and shortens itself
This would help me gain alot of Tecnical knowledge
 

MrChips

Joined Oct 2, 2009
27,113
In these times I read MOSFET shortage to mean supply shortage.
Oops, even supply shortage or supply line shortage is misleading.
You still cannot get it right with any of the following:
  1. shortage
  2. supply shortage
  3. supply line shortage
  4. supply chain shortage
  5. current supply shortage
  6. potential shortage

Maybe one ought to say “voltage short” instead.
 

Alec_t

Joined Sep 17, 2013
13,149
Basically what i want to try is to damage the Mosfet in such a way that all thee terminal of the mosfets gets permanently damaged and shortens itself
Exceeding all the rated maxima in the FET's datasheet might do that. Or it might cause open circuits rather than short circuits.
 

Papabravo

Joined Feb 24, 2006
19,262
There is no a priori reason why all three terminals would be shorted together if the device was operating within the datasheet limits. Operating outside the limits could heat the device to a point where the internal structure of the device is compromised. This could involve the breakdown of the thin oxide insulating layers or deformation of the internal structure causing a momentary short or melting the solder holding the part to the board. I don't see how knowledge of how it happened will be illuminating at all.
 

Thread Starter

Haulin

Joined Sep 23, 2022
6
What voltage or current should I exceed
Vgs= +-20v, Vds=400v and Id=23Amps
This is the basics I know of IRF 749 Mosfet
What would I do to damage all ther terminals permanently

I Alrealy tried Vgs more than 30v nothing happened it just heatsup and shortens for a small interval of time even when I connect too long

I also tried having greater than 30Amps from the mosfet at Vgs 10v
But that permanently shortens my Gate and Drain

Question is What would I do
 

Alec_t

Joined Sep 17, 2013
13,149
Question is What would I do
My question is, why would you want to deliberately destroy MOSFETs ? Most people try to avoid doing that!
You won't learn much (if anything) beyond what the datasheets already tell you. Apart from that, no two MOSFETs (even from the same batch) are identical, so the parameters for failure will likely vary from device to device.
 

Thread Starter

Haulin

Joined Sep 23, 2022
6
Alec the real reason is its not the first time my mosfets all three terminals are shorted in kinda things like UPS, Motor driver etc when making in a lab most of the time the reasons of not working is,Mosfets gets shorted out of no where
So what I want to do is try to short them up permanently so i will have some kind of knowledge of one of the reasons for shortage
 

Alec_t

Joined Sep 17, 2013
13,149
Excessive drain current, due to a faulty component downstream of the FET, would be a common cause of FET failure and resultant shorting of terminals.
If several FETs are paralleled (you refer to "all the MOSFETs in one line") to share current, failure of the weakest one puts extra stress on the others, so the next weakest fails, followed by the rest in turn.
 

Thread Starter

Haulin

Joined Sep 23, 2022
6
This is one way of getting into the fault we would like to achieve it via Overvoltage but I don't have a supply that can give 100V+ Voltage at VDS or VGS is there any way I can destroy the Mosfet using OverVoltage or Voltage Reverse polarity
I have IRFB4110 Mosfet whose VGS is +-20v and VDS is 100v, ID is 110 Amps, which I would like to destroy
I already gave VGS 30v Pwm signal and nothing happened
 

Alec_t

Joined Sep 17, 2013
13,149
Switching off the current through a high-value inductor (e.g. an old-school power transformer primary, or a car ignition coil) generates a high voltage spike; enough to destroy many FETs.
 
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