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TPS65131-Q1: Circuit review

Kazutobi
Prodigy 10 points
Part Number: TPS65131-Q1

Tool/software:

Hello, everyone.

I would like to use the TPS65131-Q1 to create a circuit that inputs +5V and outputs -9V (output current 600mA(Typ.)).

Positive power supply output is not necessary this time.

I created the circuit as shown below, but would you please review whether this circuit is correct?

Is it appropriate to leave the pins related to the positive power supply open?

Are the constants for R3, R4, etc. appropriate for outputting -9V?

If you have any other comments, please let me know.

Thank you in advance.

  • 0
    TI__Mastermind 28470 points

    Hi,

    The resistance of R3 and R4 seems to be revised, R3 should be the larger one.

    And the output current capability of VNEG might also be a limit of your spec requirements.

    BR

    Patrick

  • 0 in reply to Patrick Yao
    Prodigy 10 points

    Hello Patrick

    Thank you for your reply.
    The correct value is R3-1M, R4=133k. I made a typo. My apologies.

    Thank you for pointing out the output current.

    I have a follow-up question.

    Is there a way to pull more than 600mA on the negative side? (Would this be possible by adjusting the inductor constant or Zener constant?)

    If this is not possible, is there a chip that can output more than 1A at -9V?

    Best Regards

    Kazu

  • 0 in reply to Kazutobi
    TI__Mastermind 28470 points

    Hi Kazu,

    If you could increase the input voltage to 5.5V, then I think it might be able to output 600mA with -9V. But it is still marginal according to the curve I shared.

    The current is mainly limited by internal switching FET current capability and thermal concern. If you only need negative voltage, you can search for inverting buck-boost solutions on TI.com.

    AC/DC & DC/DC converters (integrated FET) product selection | TI.com

    BR

    Patrick