Could you tell me the permissible voltage range and time length if gate voltage of SiC module has been undershot/overshot in amoment?

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NXTY_Shibata
Level 4
Level 4
Distributor - NEXTY (Japan)
First like received 50 sign-ins 10 solutions authored

Dear IFX Community,

According the title of matter, we received this question from Japanese customer will purchase SiC modules.

If there is permissible and conclete values and times for gate overshoot/undershoot, could you tell me the information?

The detail of this question is following and described in attached PDF file.

0.Original gate bias is  seemed as +15V/-9V.  Furthermore, this SiC has already worked in buck converter at test.

Test condition: Vin=830V, Vout=400V, Pout=50kW, duration term=5 hours.

1.It's monitored undershoot of minus gate voltage, but this voltage difference is very small. (Rated: -10V <=> Monitored: -10.4V)

2.This voltage undershoot is very short term from waveform. It seems under 100ns, probably under 20 ns or less.

 I think this undershoot won't affect the SiC MOSFET, but I can't tell to customer without confirmation.

If there is any questions, please let me know it.

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1 Solution
sushank
Moderator
Moderator
Moderator
25 solutions authored 100 sign-ins 50 replies posted

hello, 

yes,  it should be avoided if the operation is in  usec, it is better to use gate driver IC for better regulation.

View solution in original post

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3 Replies
sushank
Moderator
Moderator
Moderator
25 solutions authored 100 sign-ins 50 replies posted

hello 

what is the part number of the Sic mosfet ? max and min values for the gate values are already mentioned. operating beyond the limit may affect the Mosfet. specially in the case of overvoltage. 

-10.4V is less and wont affect the mosfet for 100nsec however it should not be avoided for long period may be in usec.  

 

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NXTY_Shibata
Level 4
Level 4
Distributor - NEXTY (Japan)
First like received 50 sign-ins 10 solutions authored

Thanks for reply.

This SiC MOSFET is FF6MR12KM1, but this model will be changed to FF4MR12KM1H in near future.

Yes, I understand max/min voltage and not to be out of rating value.

>-10.4V is less and wont affect the mosfet for 100nsec however it should not be avoided for long period may be in usec.

This comment seems it's permissionable range about -10.4V for 100nsec. I think "it should not be avoided for long period may be in usec." is to be modified to "it should be avoided for long period may be in usec.", isn't it?

Is it possible to be improved with modifying gate driver? Customer uses driver for IGBT(62mm).

 

Best Regards,

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sushank
Moderator
Moderator
Moderator
25 solutions authored 100 sign-ins 50 replies posted

hello, 

yes,  it should be avoided if the operation is in  usec, it is better to use gate driver IC for better regulation.

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