• State Resolved
  • Locked Locked
  • Replies 9 replies
  • Subscribers 63 subscribers
  • Views 141 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TPS63051: About the overcurrent protection

Taku Mitani
Prodigy 90 points
Part Number: TPS63051

According to the datasheet(9.3.6 Short Circuit Protection),
It states that the output current is limited to 1.5A.

Is 1.5A the max?
Please let me know if there are any regulations for min, typ, max.

I actually tested it by shorting the TPS63051 circuit.
Output current was limited to around 420mA.
Is this value within the expected range?

Is there a large variation in Overcurrent protection?

Best regards, Taku MITANI.

  • 0
    TI__Mastermind 24605 points

    Hi  Taku,

    Could you share your set-up when you got a 420mA output current?

    For TPS63051, it is based on averange-current control and current of inductor is under control by voltage loop. Means, in buck mode, the current limit means the maximum output current; in boost mode, the current limit means the maximum input current.

    Regards

    Tao

  • 0 in reply to Tao Zhang
    Prodigy 90 points

    Hi Tao

    Thank you for your explanation.

    TPS63051circuit I designed is below.
    Overcurrent protection of 420mA was when VIN=4.0V.

    Best regards, Taku MITANI.

  • 0 in reply to Taku Mitani
    TI__Mastermind 24605 points

    Hi  Taku,

    Based on Vin is 4.0 and Vout is 3.3. I am afraid the output current limit should not be so low. Do you have waveforms about this protection to share here?

    Regards

    Tao

  • 0 in reply to Tao Zhang
    Prodigy 90 points

    Hi Tao

    I shorted Vout and GND with Toggle Switch(ON resistance < 100mΩ).
    The location of the Toggle Switch is shown in the diagram below.

    This is the waveform when Vout (3.3V) and GND are shorted with the toggle switch.

    Output current is approximately 60mA before short circuit.
    Peak 5.25A at the moment of short circuit.
    Approximately 420mA after short circuit.

    Best regards, Taku MITANI.

  • 0 in reply to Taku Mitani
    TI__Mastermind 24605 points

    Hi  Taku,

    Oh, it is reasonsable, sorry i forgot that TPS6305X has a feature that you can adjust you current limit by set different state of ILIM pin.

    In your application, the ILIM is set to 0, then, actual current limit is much smaller than normal one, see the table below. ILIM1 is default high here.

    Regards

    Tao

  • 0 in reply to Tao Zhang
    Prodigy 90 points

    Hi Tao

    Thank you for your explanation.

    In my design, ILIM0=0, ILIM1=H,
    so I understand that current limit set : 0.65 * IIN_MAX
    However, in the end, What mA is IIN_MAX?
    What mA is the output current limit?
    These are not listed in the TPS63051Data sheet.


    >Means, in buck mode, the current limit means the maximum output current;
    >in boost mode, the current limit means the maximum input current.

    According to your explanation,
    The current limit in buck mode (VIN=4.0V, Vout=3.3V) is
    Does it mean "Vout current limit = 0.65*IIN_MAX" ?

    after all, is the current of 420mA during a short circuit abnormal?
    Or 420mA is it a valid value as a current limit?

    By the way, the output current during short circuit is 420mA,
    I confirmed reappearance on 3 PCB.

    Best regards, Taku MITANI.

  • 0 in reply to Taku Mitani
    TI__Mastermind 24605 points

    Hi  Taku,

    Yes, the output current limit in your application is  0.65*IIN_MAX, here Iin_max means the current limit in boost mode. and you can find the value of current limit in DS. Please check the screenshot below.

    So, the 420mA Iout during OCP is make sense here.

    Regards

    Tao

  • 0 in reply to Tao Zhang
    Prodigy 90 points

    Hi, Tao

    Thank you again for your kind and detailed explanation.

    I see, it is calculated by converting from "Input current-limit BOOST mode".
    I think the following screenshot applies to my design.


    And since ILIM0=L, ILIM1=H,
    Buck mode output current limit(VIN=4.0V, VOUT=3.3V) : IINMAX*0.65

    According to the DATASHEET min 550mA, max1400mA, typ is not stated.
    but I estimate that "typ" is the intermediate value between min and max.
    Estimated typical value : (550mA+1400mA)/2=975mA
    Therefore 975mA*0.65=634mA
    420mA is close to the estimated typical value.

    Thanks, Taku MITANI.

  • 0 in reply to Taku Mitani
    TI__Mastermind 24605 points

    Hi  Taku,

    You are welcome, thanks for considering TI's device.

    Regards

    Tao