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POWER MOSFET gate resistor

Discussion in 'Power Electronics' started by Ftpsmb, Apr 13, 2020.

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  1. Ftpsmb

    Ftpsmb

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    0
    Apr 13, 2020
    Please help :)
     

    Attached Files:

  2. Alec_t

    Alec_t

    2,788
    742
    Jul 7, 2015
    Welcome to EP!
    R7 is not a timing resistor. It is there (a) to limit the MOSFET gate charge/discharge current to a range that the gate drive arrangement can handle and (b) to damp any high frequency spurious oscillations due to stray inductance. Its value is usually in the 10Ω to 100Ω range and is not critical.
     
  3. Ftpsmb

    Ftpsmb

    2
    0
    Apr 13, 2020
    thank you about the range! I am very in doubt if its protected, the DAQ system does have galvanic isolation, for 60V DC however I am not sure if this is enough?
     
  4. Alec_t

    Alec_t

    2,788
    742
    Jul 7, 2015
    Allowing 60V on to the FET gate will fry the FET. Most FETs have a maximum allowable Vgs of only ±20V.
    A high value gate resistor would prevent the FET turning on/off quickly, so could result in it over-heating.
    If the FET has to be switched on/off quickly then a dedicated gate-driver IC would be the best option.
     
    Last edited: Apr 14, 2020
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