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IGBT Forum Discussions

User17668
Level 2
5 replies posted 10 questions asked 5 questions asked
Level 2
Hi Infineon Team,

I have a very simple question,
can you explain easily what's the difference between IGBT & MOSFET?

Thanks a lot.
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Giuseppe_De_Fal
Moderator
Moderator 10 solutions authored 10 replies posted 10 sign-ins
Moderator
4088.attachHi Melli,
there are few analogies between MOSFET and IGBT and a main significant difference.

Regarding the analogies:
- Both IGBT and MOSFET are voltage controlled devices
- Both IGBT and MOSFET don't absorb current from the driver stage in on/off state

About the main difference:
- MOSFET is a unipolar device, that means the current flow is only due to electrons flow. On the other hand, IGBT is a bipolar device, that means that the current flow is produced by the movements of electrons (negative charged particles) and holes (positive charged particles).

As a consequence of the bipolar behavior of the IGBT, the equivalent on-state resistance of an IGBT is generally lower that the one of a MOSFET with the same voltage class. However, IGBT has a minimum voltage drop that is in the range of the one of a diode (about 0.7V), which MOSFET doesn't have (see attached picture).
In addition, the lower resistivity comes with a price: an excess of charge is stored in the IGBT during the conduction phase which leads to an increase of turn-off switching losses compared to a MOSFET, whose switching can be assumed (as a first approximation) lossless.

Hope that this helps.

Regards,
Giuseppe

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Giuseppe_De_Fal
Moderator
Moderator 10 solutions authored 10 replies posted 10 sign-ins
Moderator
4088.attachHi Melli,
there are few analogies between MOSFET and IGBT and a main significant difference.

Regarding the analogies:
- Both IGBT and MOSFET are voltage controlled devices
- Both IGBT and MOSFET don't absorb current from the driver stage in on/off state

About the main difference:
- MOSFET is a unipolar device, that means the current flow is only due to electrons flow. On the other hand, IGBT is a bipolar device, that means that the current flow is produced by the movements of electrons (negative charged particles) and holes (positive charged particles).

As a consequence of the bipolar behavior of the IGBT, the equivalent on-state resistance of an IGBT is generally lower that the one of a MOSFET with the same voltage class. However, IGBT has a minimum voltage drop that is in the range of the one of a diode (about 0.7V), which MOSFET doesn't have (see attached picture).
In addition, the lower resistivity comes with a price: an excess of charge is stored in the IGBT during the conduction phase which leads to an increase of turn-off switching losses compared to a MOSFET, whose switching can be assumed (as a first approximation) lossless.

Hope that this helps.

Regards,
Giuseppe
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