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TPS5450: What is the max current of internal MOSFET of TPS5450

Lin_Charles
Expert 4260 points
Part Number: TPS5450

Hi team,

    It is nice to know you all here. Below is the schematic how customer use TPS5450, they leave 54331 unconnected. Now they find that the input current will be larger than working current many times? What are the main reasons? How to improve such condition? Thanks

The working condition are: Vin=12V, Vo=5V/1A

Blue is the input current; There are two spike in the input current. max value is higher than 10A.

  • 0
    TI__Expert 6245 points
    Hello Charles,

    I am not used to seeing a huge input spike like you show in your scope plot. Could you get a close up of the spike and mark where you are measuring on your schematic? Also, how did you disable the 54331?

    The maximum current that this part should pass before tripping current limit can be as high as 9 A. If di/dt is large, you may see an extra ampere. It is unlikely that a typical part will pass 10 A even for a few hundred nanoseconds.

    Regards, Robert
  • 0 in reply to Robert Blattner
    TI__Expert 4260 points

    Hi Robert,

       Thank you for your response. Customer left 54331 in welded in this circuit. I have attached the waveform from customer side. You can see spike in the below waveform, the maximum current will be 12.38A. I think the load transient is slow in this circuit, we can put capacitor parallel with R374. How do you think about this solution? Also the max current of internal MOSFET of TPS5450 is 9A? Right?