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UCC21521: sink current when EN=Low

Robin Liu
Intellectual 1940 points
Part Number: UCC21521

Hi team,

when EN=low, how much the sink current of the output stage is?

Regards

Robin Liu 

  • 0
    TI__Intellectual 2805 points

    Hello Robin, 

    I work with our isolated gate drivers and I will be happy to assist you. 

    When EN = low, a low signal to transmitted across the isolation barrier much like INA or INB = low. 

    Therefore, the sink capability is the same, 6A typical.

    If this answered your question, please press the green resolved button. 

    Regards,
    Mateo

  • 0 in reply to Mateo Begue
    TI__Intellectual 1940 points

    Hi mateo,

    thanks for you reply.

    Please refer to the detail scenario as below:

     

    the customer use the UCC21521 to drive the LLC stage second side full bridge,

     

    When they try to make the full bridge works like a passive rectifier, they set EN=low. The issue is that there is a small pulse output on the Vgs of the high side SiC FET.

     

    Please refer to the picture. The low side is OK. The Vgs would be locked at 0V. but the high side Vgs, there is a small pulse.so the customer doubt the sink current ability.

     

    Could help to analysis on this? Thanks.

    the low side Vgs the high side Vgs 

    Regadrs

    Robin Liu

  • 0 in reply to Robin Liu
    TI__Intellectual 2805 points

    Hello Robin, 

    Thank you for the scope captures. 

    Is channel 1 Vds? 

    What is the SiC FET part number that your customer is using? 

    Lastly, can you post the schematic? This will help me look for issues. 

    Regards,
    Mateo

  • 0 in reply to Mateo Begue
    TI__Guru**** 189401 points
    Hi Robin,

    It's been a while since we've heard from you, so we must assume you've resolved your issue.

    If possible, please post how it was resolved for others to learn from.

    If your issue isn't resolved, let us know, and we will work with you to resolve it.
  • 0 in reply to Don Dapkus
    TI__Intellectual 1940 points

    Hi Don,

    Thanks for your response and sorry for long time no update.

    because this issue didn't  stuck the customer test&debug process, so they continue for further step.

    but this small pulse still could be a issue.

    i send you the schematic by private message. Thanks.

    Regards

    Robin Liu

  • 0 in reply to Robin Liu
    TI__Guru**** 189401 points
    Hi Robin,

    Sure, we can check the schematic and work with you to get to the bottom of this issue.