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About FAULTZ and MUTE of TPA3116

My customer has some questions about the datasheet P.19, Figure 30 of TPA3116.
That figure is important for our customer to decide their device selection.

1)
What does ">1.4s" refer to?
Does that mean it needs to wait for 1.4s or more to wake up after pulling FAUTZ down to L?

2)
The datasheet says "If automatic recovery from the short circuit protection latch is desired, connect the FAULTZ pin directly to the SDZ pin".
=>Does the automatic recovery also happen after >1.4s, not instantly?

3)
Does our customer need to set MUTE=H when FAULTZ is set to L ?
Please let us know if any problems in case our customer sets MUTE=L when FAULTZ=L.

Beat regards,
Yoshihiro Hirata

  • Hi, Hirata-san,

    1. This is the DS description "In systems where a possibility of a permanent short from the output to PVDD or to a high voltage battery like a car battery can occur, pull the MUTE pin low with the FAULTZ signal with a inverting transistor to ensure a high Z restart". The 1.4S is the system auto-recovery time when an OC event is detected. Basically assert MUTE pin before SDZ goes low.

    2. Yes, after an OC event, the IC will try to re-start after 1.4S and return to normal operation if the fault condition is removed.

    3. As mentioned before, if the is a possibility of permanent short from the output to PVDD, then assert MUTE before SDZ goes low when FAULTZ is asserted.

     

    reg,

    Paul Chen

    Audio Applications Engineer

    Dallas TX 

  • Chen-san,
    Thank you for your reply.
    We have received another questions after the answer to our customer.
    + Does FAULTZ set to "H" when OC(Over Current) Fault condition is cleared ??
    + Should we set FaultZ=L and SD=L respectively when LATCH is cleared ??
    + Can the LATCH be cleared if we set SD=L after Fault=H ??
    We would like to know of "latch clear method in non automatic recovery condition."
     
    Best Regards,
    Yoshihiro Hirata
  • My customer is a little hurry. Because they must decide the system spec in a few day.
    We have received another questions.

    Do we must MUTE pin set "H" when FAULTZ="L"(fault condition)?
    If we don't want this setting, will IC be damaged?

    I want to know the accuracy of the 1.4s?
    1.4s: try re-start from FAULTZ set to L.

    Please tell us also the previous question. It is following.

    >+ Does FAULTZ set to "H" when OC(Over Current) Fault condition is cleared ??
    >+ Should we set FaultZ=L and SD=L respectively when LATCH is cleared ??
    >+ Can the LATCH be cleared if we set SD=L after Fault=H ??
    > We would like to know of "latch clear method in non automatic recovery condition."

    Best regards,

    Yoshihiro Hirata

     

  • Hi, Hirata-san,

    SHORT-CIRCUIT PROTECTION AND AUTOMATIC RECOVERY FEATURE section in page 19 of the datasheet need to be followed to guaranteed the reliability of the IC.

    When OC is triggered, Faultz is will be set to L and stays L after the OC (fault condition) is cleared. To clear the latch, SDz need to be set to L and restart the amp to normal operation.

    When SDz is tied to Faultz, it will automatically clear the latch as mentioned in the DS -

    If automatic recovery from the short circuit protection latch is desired, connect the FAULTZ pin directly to the

    SDZ pin. This allows the FAULTZ pin function to automatically drive the SDZ pin low which clears the shortcircuit

    protection latch.

    There is no spec min/max for the auto-recovery time of ~1.4s. I would estimate +-20%.

    reg,

    Paul.

  • Sorry, but still didn't understand where ~1.4s came from.


    If FAULTZ and SDZ are tied together, then autorecovery is performed immediately. If FAULTZ and MUTE are inversely tied together, then autorecovery need to wait ~1.4s. Is ~1.4s a requirement of MUTE feature? If that's the case, then i would assume that the wait time should also be needed somewhere else when combination of MUTE and SDZ are performed.

    By the way, FAULTZ is stated to be open drain output. How it drive other input directly? Internal pullup? how strong?

  • Hi Ardian,

    When the Faultz and SDz are tied together (auto-recovery) and OC condition is encountered, the device will be shut down (output Hi-Z, Faultz=Low). The Faultz will return to H again after 1.4s to restart the device. If the OC condition still exist, the device will be in shutdown again.

    Faultz is open drain which requires an external 100K ohms resistor.

    reg,

    Paul.