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Original question:

Question of TPS25921

TPS25921A: tps25921

Minqi Zhao
Intellectual 1660 points
Part Number: TPS25921A

Dear expert,

My customer is looking for an E-fuse solution that can shut off with 400mA for 50ms. Please share your suggestions, thanks.

  • 0
    TI__Guru 57737 points

    HI Minqi Zhao,

    Can you please elaborate on what you mean by turn off with 400mA,

    • Do you want the efuse to turn off with 400mA within 50ms for an over curretn event ?
    • Or do you Do you want the efuse to turn off with 400mA within 50ms for an output short circuit event ?
  • 0 in reply to Praveen GD
    TI__Intellectual 1660 points

    Hi Praveen,

    Customer need to turn off with 400mA within 50ms for an over current event. They used TPS25921 before, but after test they found it took >1s to turn off the e-fuse, which can't meet the demand. Please share your suggestions, thanks.

     

  • 0 in reply to Minqi Zhao
    TI__Guru 57737 points

    Hi Minqi Zhao,

    It is important for you to understand how our devices react to a short circuit at the output.

    • When a short circuit is applied at the output, the current flowing from IN to OUT increases rapidly. If the current exceeds 1.5 x ILIM, the device engages a fast current clamping circuit to regulate down the current faster than the nominal overcurrent response time (tLIM). The device does not completely turn off the power FET to ensure uninterrupted power in the event of transient overcurrents or supply transients. Once the device is in current limit mode, it will turn off only when the device junction temperature reaches thermal shutdown threshold (TSD).
    • The time taken for the device to reach thermal shutdown depends on various parameters like input voltage, current limit setting, RQJA and ambient temperature.

    If all the parameters ,(Vin, Current limit setting , RQJA and ambient temperature) are low the device will take more time to erach TSD and turn off. Similarly, for the device to turn off faster these parameters need to be higher.

    All our efuse devices have similar behaviour to a short circuit at the output.

    There is one device  TPS255x which turns off after a fixed 7.5ms time duration from entering current limit mode after a short circuit event. You can check  if this device meets their requirements.