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Original question:

[FAQ] UCC27624: What is the output resistance of a gate driver?

UCC27624: Driver is heating

Mohammed Khan
Intellectual 570 points
Part Number: UCC27624
Other Parts Discussed in Thread: UCC28951

The driver is connected between ucc28951 controller and gate drive transformer to drive half bridge. I'm unable to check gate  waveforms as the driver is heating up.

I tried Vdd :15V, 12V.

Below is the circuit design.

Below are part numbers:

Transformer P/N: GT04-111-252-A

Mosfet P/N : IPW65R090CFD7XKSA1

  • 0
    TI__Expert 8660 points

    Hi Mohammed,

    It may be that the input signals are exceeding the ratings set by the datasheet. Can you send the waveforms for the input signals of the driver? If you made your own schematic, can you send that as well, alongside the layout?

    Thanks,
    Rubas

  • 0 in reply to Rubas Khalid
    Intellectual 570 points

    Salam khalid. 

    Below is the circuit. Layout is followed as per the suggested layout in the datasheet, I will share layout by tomo. 

    Above waveform is taken Vdd : 15V. After a period of few seconds , driver starts to heat. 

    Layout: 2 drivers

    Dark Blue: Signals coming from controller

    Sky blue: ground

    Purple layer Vias: Power supply

    Which part inputs are exceeding? Can you please explain. 

    To reiterate, VDD: 12V. All primary Fets and transformer part numbers are mentioned above. 

  • 0 in reply to Mohammed Khan
    TI__Expert 8660 points

    Wa salaam Mohammed,

    Typically, gate drivers can heat up due to inputting a very high frequency or signal amplitude.

    It looks like your output waveforms (assuming they were taken at your Gate-A and Gate-B test points), have a long rise/fall time, indicating a heavy load. Can you send current waveforms of the primary side?

    We also have an app note related to using gate driver transformers, which may be helpful: www.ti.com/.../slla602.pdf

    Thanks,
    Rubas

  • 0 in reply to Rubas Khalid
    TI__Expert 8660 points

    Salaam Mohammed,

    As it's been a month with no activity, I will be closing this thread. Please reply back or create a new thread if you have further questions.

    Thanks,
    Rubas