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TPS1641: About Thermal Shutdown

Part Number: TPS1641

Hi team,

If a thermal shutdown is applied, will there be any damage to the device, as it may exceed the absolute maximum junction temperature rating?
If damage is not a problem, Is there any problem with repeated thermal shutdowns?

Best,
Ryu

  • Hi Ryu,

    I will come back to you by early next week.

    Best Regards,

    Arush 

  • Hi Arush,

    I understand. I await your response.
    Please tell me one more thing.
    If the FLT pin goes low due to an IN-OUT short circuit, does the FLT pin also stay low forever after it is latched off?
    Does the FLT pin go High when the IN-OUT short circuit is restored?

    Best,
    Ryu

  • Hi Ryu,

    FLT pin restores back to high (open drain so uses the pull up resistor) when the device goes back to normal function. In datasheet you can see figure 9.8. The figure explains power on with short and in this short is not resolved but device tries multiple auto-retry. FLT pin goes high before each retry but again goes low because fault still exist. 

    Regarding your original question, thermal shutdown happens to protect the device and do not cause harm to device. On average if you keep the device inside the recommended temperature range (<125C) then the device won't get damaged due to repeated thermal shutdowns. Continuous high temperature above absolute maximum range(>150C) causes damage and thermal shutdown helps in preventing this type of damage. 

    Kindly click on resolved if I did answer your questions or reply here for further clarification.

    Best Regards,

    Arush

  • Hi Arush,

    Thanks for the reply.
    I understood that if the device is an auto-retry type device, the FLT pin will change according to the state.
    However, if it is a latch type device, I don't think it will output even if the short condition is resolved.
    I would like to know if only FLT pin goes High in this case, or if it remains Low until the latch off is resolved.

    Best,
    Ryu

  • Hi Ryu,

    Yes, it should remain low until the latch off is resolved.

    I will double-check it on hardware also and will inform you later next week (I am on leave this week)

    Best regards,

    Arush

  • Hi Ryu,

    It should latch off for IN-OUT short detection irrespective of the variant. So even if IN-OUT short is gone it will remain latched off. 

    Regards

    Kunal Goel

  • Hi Kunal,

    Thanks for the reply.
    I understand now.

    Best,
    Ryu