infineon4engi@twitter infineon4engineers infineon@linkedin infineon@youtube
twitter Facebook Linkedin Youtube

Banner_MOSFET_SiC Banner_Schottky_Diodes Banner_GateDriver_MOSFETS_SiC Banner_CoolSiC_Hybrid_Modules Banner_automotive_applications

+ Reply to Thread
Results 1 to 2 of 2

Thread: Characterization of MOSFETs vs IGBTs

  1. #1
    New Member New Member gabyft45ol is on a distinguished road
    Join Date
    Mar 2020

    Characterization of MOSFETs vs IGBTs


    The switching parameters of IGBTs are characterized by a double-pulse test with an inductive load. The switching times (Tdon, Tr, Tdoff and Tf) are defined in relation with the collector current (Ice).
    For the MOSFETs (such as SiC MOSFETs), a resistive load is used for the test. The switching times are defined in relation with the drain source voltage (Vds).

    My questions are:
    Why do we prefer an inductive load for IGBTs? Why the switching times are not measured in relation with the collector voltage (Vce) ?
    Why do we always use a resitive load for SiC MOSFET? Can the switching times be defined by the drain current (Ids) or they need to be defined by the drain voltage (Vds) ?

    For the context: I need to determine the minimum dead time for two power converters, one made of SiC MOSFETs and the second one made of IGBTs.

    Thanks in advance

  2. #2

    Infineon Employee
    Infineon Employee
    electricuwe is on a distinguished road
    Join Date
    Sep 2019
    Hello Gabriel,

    to understand this application an device background is needed.

    The main application of IGBT are inverters consisting of halfbridges for drives or for feeding renewable energy into the grid. In this case the load -seen in the µs timeframe- is an inductive load, either the motor stray inductance or a filter inductance. The IGBT, regardless of the voltage class, is well suited for this applications as it is usually combined with a decent separate freewheeling diode.

    The applications of Mosfets are much more diverse. Many Mosfets are used as single switches without the need to have a fast antiparallel diode. Si-Mosfets for low voltage (up to 200 V) do have intrinsic body diode capable of fast commuation as well. But Si-Mosfets for higher voltages have a very poor body diode and are usually not applicable in halfbridge circuits working with inductive load.

    SiC-Mosfets in the whole voltage range either have a usable bodydiode (as our CoolSiC-Mosfet) or are combined with separate freewheeling diodes (as most SiC-Mosfets from competition). In both cases the devices are suitable for operation in halfbridges working on inductive loads and hence can now enter typical IGBT applications.

    A recommendation for setting and verifying the deadtime in IGBT designs you can find here:

    Most of this is applicable to SiC-Mosfet designs as well. Due to lower switching losses Inverters with SiC-Mosfets can be operated with higher switching frequency compared to IGBT inverters. To avoid detrimental effects on output voltage waveform or behavior in a control loop, the deadtime should not be bigger than appox. 1% of the switching frequency periode. To achieve this strong drivers with low tolerance and variation of propagation delay are required.

    Best regards,
    The views expressed here are my personal opinions, have not been reviewed or authorized by Infineon and do not necessarily represent the views of Infineon.

+ Reply to Thread

All content and materials on this site are provided “as is“. Infineon makes no warranties or representations with regard to this content and these materials of any kind, whether express or implied, including without limitation, warranties or representations of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. No license, whether express or implied, is granted by Infineon. Use of the information on this site may require a license from a third party, or a license from Infineon.

Infineon accepts no liability for the content and materials on this site being accurate, complete or up- to-date or for the contents of external links. Infineon distances itself expressly from the contents of the linked pages, over the structure of which Infineon has no control.

Content on this site may contain or be subject to specific guidelines or limitations on use. All postings and use of the content on this site are subject to the Usage Terms of the site; third parties using this content agree to abide by any limitations or guidelines and to comply with the Usage Terms of this site. Infineon reserves the right to make corrections, deletions, modifications, enhancements, improvements and other changes to the content and materials, its products, programs and services at any time or to move or discontinue any content, products, programs, or services without notice.