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Fränce
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Good morning everyone,

One thing that is not clear to me:
How is the input capacitance influencing the IGBT switching transient?

Thanks for your answer!
Fränce
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Giuseppe_De_Fal
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Hi Fränce,

the answer provided before is substantially correct as it gives an overview of the different parasitic capacitances inherent to an IGBT structure.

Regarding the impact of the capacitances on the switching transient of an IGBT, I just want to add that mainly the Cies and Cres are responsible to determine the turn-on rate of change of the IGBT voltage whilst the Coes is mainly responsible to the rate of change of the output voltage of the IGBT during the turn-off.

In general, reducing the parasitic capacitances is beneficial as it makes the device switching faster, without changing the gate driver stage. Additionally, a lower Cies capacitance also reduces the power losses in the gate driver IC.

Hope that this provides an overall comprehensive picture about the impact of  parasitic capacitances of an IGBT.

Best Regards,

Giuseppe

 

 

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IGBT_Wizzard
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Hi Fräncis
the dynamic characteristics of an IGBT are influenced by several parasitic capacitances. These are inherent parts of the die’s internal structure.
The input capacitance Cies and the reverse transfer capacitance Cres are the basis for an adequate dimensioning of the gate driver circuit.
The output capacitance Coss limits the dV/dt at switching transitions.
For much more details, please see the following application note:

https://www.infineon.com/dgdl/Infineon-AN2011_05_IGBT_Modules_Explanation-ApplicationNotes-v01_02-EN...
TS
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Giuseppe_De_Fal
Moderator
Moderator 10 solutions authored 10 replies posted 10 sign-ins
Moderator

Hi Fränce,

the answer provided before is substantially correct as it gives an overview of the different parasitic capacitances inherent to an IGBT structure.

Regarding the impact of the capacitances on the switching transient of an IGBT, I just want to add that mainly the Cies and Cres are responsible to determine the turn-on rate of change of the IGBT voltage whilst the Coes is mainly responsible to the rate of change of the output voltage of the IGBT during the turn-off.

In general, reducing the parasitic capacitances is beneficial as it makes the device switching faster, without changing the gate driver stage. Additionally, a lower Cies capacitance also reduces the power losses in the gate driver IC.

Hope that this provides an overall comprehensive picture about the impact of  parasitic capacitances of an IGBT.

Best Regards,

Giuseppe

 

 

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