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TPS22913BEVM-656: tps22913

Michael XU
Prodigy 40 points

Part Number: TPS22913BEVM-656

Dear Sir,

We are using TPS22913B in our optical transceiver, but have the Vin inrush current issue:

The related schematic and tested inrush current as below:

Question material for TI forum.pdf

Questions:

1. What is the root cause of first inrush current peak?

2. How to delete or decrease this inrush current?

  • 0
    TI__Genius 13650 points

    Hi GJ,

    Thank you for reaching out to the E2E forum!

    From the waveform I can see the inrush current spike at VIN is occurring before the part is actually turned on. A cause for this could be that the input capacitor is drawing the inrush current to charge up when power is applied. By measuring the current at the output you can observe if this inrush current spike will have an effect on any downstream loads.

    In order to troubleshoot this even further I would need a scope capture with Vin, Vout, Von, and the current when this event happens.

    Regards,

    Andy Robles

  • 0 in reply to Andy Robles
    Prodigy 40 points

    Hi, Andy,

    Thanks for the feedback.

    We got this result with input capacitor C33 be removed. please see the attached pdf file in last email: The actual selected value of the components as: L9: 0 ohms SHORTED;   C27:NC;   C31:0.1UF;   C33:NC

    But the first inrush current spike still be exist.

    Regards,

    Michael

  • 0 in reply to Michael XU
    TI__Genius 13650 points

    Hi Micheal,

    Thank you for the clarification.

    In order to be able to assist you in trouble shooting this event I would have to get the information that I mentioned before, a scope shot with VIN, VOUT, VON, and the current at the time of the event.

    Regards,

    Andy Robles

  • 0 in reply to Andy Robles
    Prodigy 40 points

    Hi, Andy,

    We do not have the suitable equipment for the testing of VIN,VIOUT, VON. Would you please provide the Pspice PDF documents for me? including tps22913B and tps22915B. 

    Thanks!

  • 0 in reply to Michael XU
    TI__Genius 13650 points

    Hi Michael,

    You can download our PSpice files from the "Design & Development" tab on the product page on ti.com. Here are the links that will take you straight to this tab.

    TPS22913 - www.ti.com/.../toolssoftware

    TPS22915 - www.ti.com/.../toolssoftware

    Without the scope shots of VIN,VIOUT, VON it is difficult to deduce what is going on with the device but here are a couple questions that might allow me to make some suggestion on what I think the problem could be:

    1. Is the first inrush current occurring during a power up event? (e.g. power supply turning on at VIN, power supply turning on for ON pin)

    2. Is the inrush current being measured at the input or at the output of the device.

    3. Any additional information would be helpful. From the scope shot i see that the inrush current is occurring about 5ms before the device actually starts conducting current, (i.e. device is enabled), so I just want to get an understanding of the what is going on at the time of the first inrush current.

    Regards,

    Andy Robles

  • 0 in reply to Andy Robles
    Prodigy 40 points

    Hi, Andy,

    The issue was resolved. thanks for your support!