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TPS628502-Q1: TPS628502QDRLRQ1

kiran kumar
Prodigy 10 points
Part Number: TPS628502-Q1

I am using "TPS628502QDRLRQ1" component in my design for getting 1.25V
I would like to know when the PG (Power Good ) signal will be triggered with respect to output voltage and how to test PG ?


I want to know the behaviour of Power Good (PG) signal and I need to perform testing. When PG will be triggered and how to test it

  • 0
    TI__Expert 7605 points

    Hi,

    Thanks for your question. I would advise you to refer to section 9.3.6 of the datasheet for these details.

    The PG pin will rise when the FB pin voltage reaches ~95% of its nominal value (0.6V).

     

    You can easily test this parameter plotting both VOUT or FB and PG on an oscilloscope.

    Thanks,

    Stefano

  • 0 in reply to Stefano Panaro
    Prodigy 10 points

    Hi

    Please let me know how PG will rise?

    When the regulator is running then I tried to change the resistor at FB pin to raise the FB pin voltage. But only out put voltage only changing by maintaining FB pin voltage constant at 0,6V. I think due to loop stabilization inside the regulator, FB pin voltage is maintained constant from inside by changing only output voltage. So on this how I can change FB pin voltage to test PG functionality ?

    Thanks and Regards

    VNS Kiran Kumar

  • 0 in reply to kiran kumar
    TI__Expert 7605 points

    Hi Kiran,

    The FB voltage will be regulated by the control loop during operation. Changing the resistors will only change the resulting VOUT.

    The easiest way to see PG functionality is directly at startup/shutdown. After the device has been enable, the VOUT starts ramping up and once it reaches 95% of the nominal value also the PG pin rises. You have the opposite behavior at shutdown.

    If you want to see a PG transition during operation, you should find a way to bring VOUT out of regulations. A simple way could be to use a high load transient resulting in an output overcurrent. This will bring down VOUT and therefore also the PG voltage. A more complicated approach could be to force a triangular waveform on VOUT with a power line amplifier and see how the PG pin reacts to it. With this approach, you should pay attention not to damage the device and keep the VIN stable.

    Thanks,
    Stefano