• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 62 subscribers
  • Views 1476 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS54160: About UVLO of Sprit-Rail.

watanabe
Expert 1740 points
Part Number: TPS54160

Hi,

My customer has a question.

Q1.

When setting UVLO with split-rail,
Can I use the formula of Datasheet P16 (2) (3) as it is?

Datasheet P16 formula.

Is this circuit correct?

Best Regards,

Watanabe

  • 0
    TI__Expert 4100 points
    Hello,
    We will look into your circuit tomorrow and get back to you with any comments.
    Regards
    Brani
  • 0 in reply to Brani Dubocanin
    TI__Expert 4100 points
    Hello,
    The equation is correct, however you will need to adjust stop voltage so that input voltage has to drop by the (output voltage + hysteresis voltage ) to shut down the supply.
    Your schematic looks good, but i did not check every single component value.
    Please refer to the application note below for details regarding design with LM54160 device
    www.ti.com/.../slva369a.pdf

    Hope this helps,
    Best regards
    Brani
  • 0 in reply to Brani Dubocanin
    Expert 1740 points
    Hi,

    Thank you for your support.
    My customer has a question.

    Q1.
    In the inverting circuit, even if a normal uvlo circuit is implemented,
    I think Vstop can not be used.

    Is there a circuit that allows Vstop to be used with an inverting circuit?

    Q2.
    Stop Vin for 20 ms,
    When restarted,
    Input current near 2A flows for 130 ms.

    After that, the power supply will start up normally.
    Does the above operation damage the IC?

    Best regards
    watanabe
  • 0 in reply to watanabe
    TI__Expert 4100 points
    Hello Watanabe,
    Here are answers to your questions:
    Q1: I think your observation of not being able to use Vstop is correct.
    However if you want to be able to adjust UVLO and start stop for your circuitry it is recommended to use some type of level shift.
    Here is application note that describes in great detail how to do level shifting for inverting buck/buck boost applications.
    www.ti.com/.../slva540.pdf

    Q2: What are the conditions when this short stop (for 20ms) is performed?
    From you description it looks like part may be re-starting without going through soft start cycle, resulting in large current flowing into IC.
    If you discharge output prior to re-start do you see same behavior or not?

    Best regards
    Brani
  • 0 in reply to Brani Dubocanin
    TI__Expert 4100 points
    Hello Watanbe,
    Thre is also spreadsheet that could be used to calculate parameters for split power supply.
    Here is link
    www.ti.com/.../swiftposneg-calc

    Regards
    Brani
  • 0 in reply to Brani Dubocanin
    Expert 1740 points
    Brani,

    Thank you for the application note of the level shifter circuit.

    Regarding Q2, Brani's view was right.
    When a large current was flowing, it did not go through soft start.
    When the output capacitor is discharged,
    Soft start works and high current does not flow.

    Thank you for your support.

    Regards
    watanabe