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Gate Driver ICs Forum Discussions

User17665
Level 1
Level 1
5 questions asked First question asked First reply posted
Dear all,

I have a question regarding CMTI:

1) Why is CMTI important in a gate driver IC?
2) What CMTI is recommended?

Thanks in advance!

Gyro
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1 Solution
electricuwe
Moderator
Moderator
Moderator
First question asked 5 sign-ins 25 replies posted
Dear Gyro,

when switching SiC-Mosfets with a strong driver, a low gate resistor value and low additional parasitic capacitance dV/dt values of 50..100 kV/us can be reached. This is good to minimize losses, but there are also detrimental effects on the system:

- a driver IC with insufficient CMTI might generate erroneous gate signals in case the internal signal transmission gets corrupted
- current spikes will be injected to the control side even across the smallest parasitic capacitance

If you anyhow limit dV/dt by larger gate resistors -e.g. in a drive application- of course also you driver will only see moderate stress.

Best regards,

electricuwe

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electricuwe
Moderator
Moderator
Moderator
First question asked 5 sign-ins 25 replies posted
Dear Gyro,

when switching SiC-Mosfets with a strong driver, a low gate resistor value and low additional parasitic capacitance dV/dt values of 50..100 kV/us can be reached. This is good to minimize losses, but there are also detrimental effects on the system:

- a driver IC with insufficient CMTI might generate erroneous gate signals in case the internal signal transmission gets corrupted
- current spikes will be injected to the control side even across the smallest parasitic capacitance

If you anyhow limit dV/dt by larger gate resistors -e.g. in a drive application- of course also you driver will only see moderate stress.

Best regards,

electricuwe
0 Likes