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UCC21550-Q1: Input power increase during VCC UV condition

Scarlett Cao
Expert 4030 points
Part Number: UCC21550-Q1

Tool/software:

Hi team,

During customer application of UCC21550-Q1, there could be some short time UV of VCCI from 5V to 2V. At is condition VCC UVLO will be triggered, and VCCI pin input current will increase to up to 0.24A. Could you help us understand why when VCC UV, its current will increase? Is this dependent on the PWM input status or anything else? Will this cause device damage risk (such as exceeding input side power limitation)?

Thanks

Scarlett

  • 0
    TI__Intellectual 1925 points

    Hi Scarlett,

    Input PWM may be what is causing this input current you are seeing. If the input pin (INx) is still at 5V and the VCCI pin is at 2V, then this would be supplying a voltage to the INx pin that is outside of the absolute maximum specs which can potentially cause gate driver damage. This difference between input pin voltage and VCCI voltage may be what is causing the current increase. I would recommend to double check the VCCI power rail to try to mitigate the noise on the VCCI pin as best as possible.

    Best regards,

    Will