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TPS546D24A: FW Question

Qiang Ren
Intellectual 2095 points
Part Number: TPS546D24A


Tool/software:

Hello Team,

We notice that in the FW, we said pause 2000, pausing for STORE_USER_ALL hold time in the FW. Does it mean that we need to wait for 2000ms before executing the next step "resetting the device"? What may happen if we don't pause 2000ms? Thanks!

Regards,

Qiang

  • 0
    TI__Mastermind 32420 points

    Hello Qiang, 

    Not allowing at least 100ms for the device to complete the NVM burn can result in a corruption of NVM and a POR fault on subsequent power on resets. TI recommends disabling regulation, and waiting a minimum of 100 ms before continuing, following issuance of NVM store operations.

    Thanks 

    Tahar

  • 0 in reply to Tahar Allag
    TI__Intellectual 2095 points

    Tahar,

    In our test system, we follow the loading requirement. We wait 100ms after each STORE_USER_ALL command.

    It works well in most products, but recently we encountered 3pcs failure samples. We suspected the waiting time is not long enough.

    After checking the CSV file generated by TI official program which is used to instruct our loading instrument.

    We found below information

    It requires to pause 2000, we want to know whether the unit of 2000 is ms.

    Please help us to check this instruction.

    We are considering to add extra time after STORE_USER_ALL  command and set this information as reason for the change.

    Regards,

    Qiang

  • 0 in reply to Qiang Ren
    TI__Guru 56985 points

     

    The TPS546D24A needs time to execute the STORE_USER_ALL command. 

    This command includes converting the PMBus values into NVM stored values, erasing the existing NVM stored values, writing the new NVM stored values, storing the values into the NVM cells, reading back the stored NVM values, and validating them against the intended values.

    If AVIN is powered down prior to the completion of this process, the NVM write process may not be complete and the values stored to NVM may not be properly retained.  This will be detected by the TPS546D24A on it's next power-on by a MEM error reported in STATUS_CML.  As a fail-safe, the output will not be enabled.  ON_OFF_CONFIG will be set to require both CNTRL and OPERATION commands and VOUT_COMMAND will be set to 0V, ensuring the output does not power-up with a corrupted NVM value.

    The NVM store process takes approximately 100ms, but some additionally margin may be required to cover all devices.  Due to tolerance of the internal clock, programmer clock, and the delay between the stop-event of the STORE_USER_ALL command and the programming script's pause command, A minimum production wait of 150ms would be recommended prior to lowering AVIN.

    PAUSE statement in the FUSION Digital Power Designer programming script exports is an option when exporting a programming script.  FUSION defaults to 2000ms in order to cover all TI programmable products, not just the TPS546D24A.

    The PMBus command "RESTORE_USER_ALL"  (Send Byte to Command code 0x16) can also be used to restore the NVM values for verification without resetting AVIN if desired.