Detecting counterfeit 4110 mosfets

[dnmun]

i agree with jeremy on this. the skill to make the parts walks in and out the door everyday. the process equipment, etching and lithography is all fairly universal now, especially since all the power parts are made in china now too. so i think it is possible that the performance is higher than other power mosfets, and it is the engineer who knows how to adjust the process to get the conductivity down to the 4mohm range. the BV and Rds may also just be from binning parts as they come out of the process and they find some lots are better than others, so they go into the FB4110 clone box. jmho

 

[methods]

Ok then.
We need a test.

My offer still stands to supply real IRFB4110's to anyone who wants to run the test.
Just PM me.

-methods

 

[CamLight]

I'll do the testing.

I have a 300A, 5V power supply and my electronic load can handle 3200W (just bumped it up from 2KW this week) at 750A so I can give those FETs a good workout. I can run them in "burst" mode where I can give them 100mS pulses a few seconds apart and also at various constant-current levels to check IR at various temperatures. I have a 6-1/2 digit DMM that can store min, max, and avg voltages and current so tracking the IR changes with temperature should be pretty easy. If not, I'll drag out the scope.

I'll need three of each FET though, real and "counterfeit".
PM coming your way methods.

 

[liveforphysics]

Thank you so much Camlight! Sounds like you are just the guy to do the testing!

-Luke

 

[methods]

Sounds great.

I can send you 13 of the real fets.
I know that ebay has one variation of the fake fets.
Several people around here bought a batch.

Doc has the second type in that xlyte controller he just bought

Lets see what we can do.

-methods

 

[CamLight]

Methods, just send me three of the real ones. Unfortunately, I wouldn't be able to use any of the others in my projects and I'm sure there are other folks here who can.

Anyone willing to part with up to three of their "fake" FETs?
Can we get a group buy together for a few of the ebay FETs?
Doc, are you going to replace your FETs? If so, it would be great if you could send me three.

 

[Doctorbass]

Methods, just send me three of the real ones. Unfortunately, I wouldn't be able to use any of the others in my projects and I'm sure there are other folks here who can.

Anyone willing to part with up to three of their "fake" FETs?
Can we get a group buy together for a few of the ebay FETs?
Doc, are you going to replace your FETs? If so, it would be great if you could send me three.

John, How many do you need to do yor test with great repetability and accuracy? I'll send you the number you need.. up to 18 :wink:

I just want to use REAL mosfet... counterfait mosfet will never interest me since they present a risk of blowing something... I dont want to have to repair the driver side of one of these new 18 fets controller!.. so the best fets are a must!

I will try to unsolllder them t the bgini of the week.

Doc

 

[CamLight]

John, How many do you need to do yor test with great repetability and accuracy? I'll send you the number you need.. up to 18 :wink:

I just want to use REAL mosfet... counterfait mosfet will never interest me since they present a risk of blowing something... I dont want to have to repair the driver side of one of these new 18 fets controller!.. so the best fets are a must!

I will try to unsolllder them t the bgini of the week.

Doc

Doc,
Three is the minimum, 5 is great. Any more than that and I'll just find more ways to blow them up.

 

[wrobinson0413]

.

 

[methods]

Hmmm... Different fets on ebay now.
These look the same as Docs

Ebay Fets

Doc - let me know how much shipping is and I will PayPal you reimbursement. Thanks for helping out with this.

CamLight- I will ship the fets out to you tonight.

As far as testing - I think that if we can just test the two fets in the same way we can illuminate differences. Perhaps we can not produce numbers that can be compared outside of this experiment but we can certainly prove once and for all that the counterfeit fets are inferior to the true IRFB4110's.

-methods

 

[CamLight]

Just some info for whoever is planning to test these fets. <snip> Another detail is that doing these tests is a bit of a pain because you need to set up the tests and it takes time to do it right. Have fun :wink:

Thanks for the info on your experiences!
I agree with you regarding testing to spec and about studying the test conditions very closely. And I'm am quite sure, based on the testing I did when selecting MOSFETs for my electronic loads, that it will take several times longer to set up the tests than it will to perform them.

methods, I agree. We don't necessarily need to test to the published specs. We can create a couple of tests that will best show the differences between these FETs and/or show their effectiveness for their intended use in a controller. For example, wrobinson0413 mentioned that Rds-on testing is done by the manufacturers with a short pulse to keep the temp at 25C. But, a controller will keep pulsing that FET as it's being used so we could just track Rds-on vs. time and/or temperature as it heated up using a specific pulse waveform.

For anyone who can contribute FETs to the cause...
Please chime in! We need to get them all here before I start these tests. Once I get going, I'll be going through all the tests and then that's it...on to the next project. I won't be able to leave the test rig set up waiting for additional FETs to arrive. To many other things to keep working on.

 

[methods]

I shipped my fets.

If nobody ships you some by mid week then either I will buy some on ebay and drop-ship them to you or I might be able to get Bob to send you a few.

-methods

 

[Doctorbass]

Methods, i'm a littloe more busy than i expected... so if you can have the fake fets on ebay, that's ok..

for me sending mosfet include spending time to disassemble the last working 18 fets controller i have now...

and i'm spending time to finish my battery BMS now.. I need it working asap..

Doc

 

[methods]

Thats fine doc, don't worry.
I am going to try to get Bob to ship a few as I think I remember him telling me that he had a few.

-methods

 

[CamLight]

methods,
I received the 5 genuine IRFB4110 FETs today...thanks!
I'll start the testing as soon as I receive the fake ones. This gives us time to define the desired tests. How about...

UPDATED WITH ADDITIONAL TEST SUGGESTIONS

- Drain-Source leakage current at 100V Vdss at 25C.
To compare standoff voltage ratings.

- On-state resistance vs. temperature at 20A constant-current, (25C-175C junction temp).
To compare heating at the high range of typical current draw. A value other than 20A is OK. I just want to pick one current value as this is all about temperature and testing at multiple current values won't tell us much more. This test can be done with and without a heat sink but I don't think that will give us any useful info. It will just affect the timing, not the Rds-on vs, Temp data. In fact, using a decent heat sink can allow for a slower rise in temp to help in plotting the data more clearly.

- Turn-on and turn-off time with a single high-amp constant-current pulse...50A?
To compare gate capacitances.

- Body diode voltage drop at -20A.
To test reverse current heating.

- Max drain-source voltage before failure at 25C.
To test max controller voltage that can be used. All devices in my possession will be tested to try to get a statistically valid value or at least a range. Voltage will be incremented in 5V steps and held there for 1 minute before proceeding. Leakage current will be recorded for each voltage.

- Run time before failure at 110V at constant 20A, 50% duty cycle.
To test ability to survive overvoltage at high temperature, probably 150C junction temp. Done at elevated temp in order to simulate temp during use. Considerable degradation of the breakdown voltage can occur over time at high temperatures due to internal contaminant migration.

Gate voltages will be the same for each test, 10V and GND.

 

[Doctorbass]

Camlight, can you please use one to test the max voltage it can take before shorting?.. in other words, if we use them with a controller that have 105 or 110V.. does it work?

About the test above 100V, i know that lowel or fechter? already drived up tp 112V ( i know this is risky.. but the gola here is to know what is the mac battery voltage wi can use with them when they are fresh charged...

ex: my 12 fets controller have these IRFB4110 and i operate it at 100.8V fresh charged no prob every days.. but let say we have 102.6V.. 103V.. etc...

cause my plan about the drag race is to use them at 103.6V (28s of 3.700V A123) fresh of the charger.. otherwise i'll need to drain the few mAh of the fresh charge to drop it to a voltage more" secure"...

Doc

 

[methods]

I agree about probing the max voltage, that would be a good destructive test.

After all the other tests are done:

1 unit could be taken up in voltage to destruction
1 unit could be taken to 106V and cycled heavily

Another test would be to investigate the heat from the forward drop across the bypass diode.

-methods

 

[CamLight]

Good ideas about the max voltage testing. I'd like to have at least 10 of each kind of FET for this though because if the numbers are all over the place for the few I have, it won't mean anything.

[Edit] LOL...I've been looking at the tests and I'll need at least 20 of each. C'mon folks, start mailing those FETs!

 

[gip_mad]

I just found this post, but i ordered my fets from ebay a month ago.... So now I have 10 "FB4110" on hand. Damn. I hope the test results will be not that bad, meanwhile I'll wait to install them on my controller.
Since I was going to build my own controller, may I ask for another test? I was just curious to see the different switching times when I put 5V or 12V to the gate.
Also, the results should be published on a website for future reference.

Thank you very much for your effort! 8)

 

[methods]

Good ideas about the max voltage testing. I'd like to have at least 10 of each kind of FET for this though because if the numbers are all over the place for the few I have, it won't mean anything.

[Edit] LOL...I've been looking at the tests and I'll need at least 20 of each. C'mon folks, start mailing those FETs!

I can send you 15 more of the real fets.

-methods

 

[CamLight]

I just found this post, but i ordered my fets from ebay a month ago.... So now I have 10 "FB4110" on hand. Damn. I hope the test results will be not that bad, meanwhile I'll wait to install them on my controller.
Since I was going to build my own controller, may I ask for another test? I was just curious to see the different switching times when I put 5V or 12V to the gate.
Also, the results should be published on a website for future reference.

Thank you very much for your effort! 8)

Thanks gip_mad!

I'm thinking that since the gate driver will reach 5V quicker due to fixed voltage rise vs. time of its output that the FET, by definition, will reach its Rds-on value for a 5V Vgs before it reaches its Rds-on for a 12V Vgs?

I think that the difference in the Rds-on value would overhwhelm any difference in heating due to the FET switching for either voltage and that a decent gate driver would be able to compensate for any differences that might be there (if my above statement is wrong).

Not sure though...thoughts anyone? :? :?

 

[CamLight]

I can send you 15 more of the real fets.

-methods

Thanks methods!
If I can get a decent number of fakes, let's do it.
Doc, I'll need all 18 of yours.

Though, I guess I could just run a bunch of overvoltage tests on the extra real ones if i don't get enough fakes.

 

[Doctorbass]

I can send you 15 more of the real fets.

-methods

Thanks methods!
If I can get a decent number of fakes, let's do it.
Doc, I'll need all 18 of yours.

Though, I guess I could just run a bunch of overvoltage tests on the extra real ones if i don't get enough fakes.

no prob.. let me take time to beat that speed record and i'll do that! :wink:
Doc

 

[methods]

Bob got back to me and no dice, he does not have any to spare.
Looks like we need to wait for Doc.

I will try to get around to shipping the rest of those fets this weekend.
Feel free to do anything you want with the first 5 - I just ordered another 1,000 IRFB4110's

-methods

 

[gip_mad]

What? Bob who? So there is a problem sending him fake mosfets? Well, I could send him mine.... But I think it will take weeks (I'm in Italy). I think we're better buying them from ebay and have them sent to him. I am willing to pay half the price.
Or, just pm me your address and I'll send them asap. I have 10 of them.

Btw... methods, are you going to sell us some 4110s?? I'm in for 10 if it's a good price...