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Fränce
Moderator
Moderator 5 sign-ins 5 replies posted 10 questions asked
Moderator
Hello,

How does the Miller plateau level of an IGBT relate to the load current?
Thank you! 🙂
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akbarsyeda
Employee
First question asked First solution authored First reply posted
Employee
Hello Fränce,

During the switching transition, the device operates in active region, the current through the device is proportional to the gate emitter voltage (as can be seen in the figure below) and can be given as: Ic ~ gfs*Vge (where gfs is the transconductance of the device). This shows, in order to allow a higher current through the device, the gate-emitter voltage should be high.

Let’s take the example of turn-on transition, the IGBT begins to conduct when the gate-emitter voltage rises above the threshold voltage. Vge continues to rise until the plateau region is reached, where the current through the device reaches its steady state value (that is determined by the load current). Hence, Vge_plateau settles to a value that allows the IGBT to deliver the load current. Evidently, when the load current is high, Vge plateau level is also high.

5273.attach

Hope this helps.

Best regards,
Qurat

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akbarsyeda
Employee
First question asked First solution authored First reply posted
Employee
Hello Fränce,

During the switching transition, the device operates in active region, the current through the device is proportional to the gate emitter voltage (as can be seen in the figure below) and can be given as: Ic ~ gfs*Vge (where gfs is the transconductance of the device). This shows, in order to allow a higher current through the device, the gate-emitter voltage should be high.

Let’s take the example of turn-on transition, the IGBT begins to conduct when the gate-emitter voltage rises above the threshold voltage. Vge continues to rise until the plateau region is reached, where the current through the device reaches its steady state value (that is determined by the load current). Hence, Vge_plateau settles to a value that allows the IGBT to deliver the load current. Evidently, when the load current is high, Vge plateau level is also high.

5273.attach

Hope this helps.

Best regards,
Qurat
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