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TPS53679: Questions of TPS53679+CSD95410

Jimmy Lai
Expert 6845 points
Part Number: TPS53679

Dear Team,

We found that the 2+1PH power supply was not powered on, and we use external power to supply it (12V, 3.3V, 5V, EN of the controller, EN of DrMOS) was normal. 

Please help to find out the reason. Attached are the waveforms of my test VOUT and IOUT, as well as the alarms read out using the GUI.
Could you guide us how to resolve these issues? Thanks a lot.







Many Thanks,

jimmy 

  • 0
    TI__Expert 8960 points

    Hi Jimmy,

    Make sure the input power sequencing is correct. The correct order is 3.3V, 5V, 12V, then VR_EN. There should be several ms between each step of the power sequence.

    Also, check for errors in Fusion after raising the 12V rail, but before raising VR_EN. You'll need to press "clear faults" in Fusion.

    Thanks,

    Travis

  • 0 in reply to Travis Williams
    TI__Expert 6845 points

    Hi Travis,

    Thanks for your great support.

    We have check the power sequence first and Lset/VOS but we still can’t power on. (enable is the last signal and RLset=15k)

    I have sent the schematic to you by mail. could you give us some suggestion on this? Thanks a lot.

    The Lset resistance of Rail2 is the same as that of Rail1, both are set to 15k; after pressing clear fault, as shown in the figure below, there is a UVF alarm as below,

    Many Thanks,

    Jimmy

  • 0 in reply to Jimmy Lai
    TI__Expert 8960 points

    Hi Jimmy,

    Try disabling the UVF protection and see if the output powers up, or if the controller is at least sending PWM. Also, ensure the feedback is connected (unlikely to be issue, but should be checked before disabling UVF).

    Thanks,

    Travis

  • 0 in reply to Travis Williams
    TI__Expert 8960 points

    Hi Jimmy,

    I'm closing this thread due to inactivity. To reopen the thread, reply to this post.

    Thanks,

    Travis