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TPS7A20: Asking for the TPS7A2018 OCP design suggestion

SHH
Mastermind 32326 points
Part Number: TPS7A20


Hi Sir,

 My customer would like design TPS7A2018 and customer would like to confirm the OCP behavior.

 

The OCP range is from 360mA to 730mA.

What the Vout will happen if some TPS7A2018 trigger min OCP 360mA spec? Will Vout drop or shutdown directly if there is inrush 680mA?

how long will TPS7A2018 trigger the brickwall current limt? What is the TPS7A2018 foldback voltage?

Thanks for help!

 

 

 

BR,

SHH

  • 0
    TI__Guru 50025 points

    Hi SHH,

    I've reached out to a designer to see if we can get some sort of estimate of the VFOLDBACK. Since it's not specified it might not be a very constant number but we will see.

    If there is sufficient inrush current that triggers the brick wall OCP on startup, what should normally happen is the OCP allows a constant current through, which will charge the output capacitor. If the unrush current is large enough to trigger the foldback OCP, the output should still have a means of coming up because the part should still output I_SC as shown in Figure 7-1 and specified in the EC table. 

    Regards,

    Nick

  • 0 in reply to Nick Butts
    TI__Mastermind 32326 points

    Hi Nick,

    customer would like to use current limit min point 0.36A to evaluate inrush current 0.68A,

    the inrush current timing is short, even trigger brick wall OCP  or foldback OCP, will the Vout rise to normal target voltage，is that right？

    regarding to datasheet, what is the brick wall OCP and foldback OCP?

    BR,

    SHH

  • 0 in reply to SHH
    TI__Guru 50025 points

    Hi SHH,

    If the brick wall OCP is triggered (but not the foldback OCP), the output will still come up because the LDO will source a constant current to the output. Is this inrush current they are expecting (680mA) due to the output capacitor? If so, I believe the output will still come up even if the foldback current limit is reached because the LDO will still source current to its output during foldback current limit even in the most extreme case, and so the output will still have a way to come up.

    Regards,

    Nick