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Original question:

TPS2546: Power auto reset when changing mode

TPS2546: Charging current issue on Samsung product

April Jiang
Intellectual 830 points
Part Number: TPS2546

      I have an issue on TPS2546. Customer Bizlink dongle, C to A, C connect to NB, A connect Samsung product.  We find below issue.

  1. When Samsung product is in open status, charging current is 1A.
  2. When Samsung product is in close status, charging current is 0.5A.

Waveform shows different waveform on D+D-, plus CTL pins. Please check the attachment, and help to check if any risk here.

Thanks,

D+ D-.zip

波形.zip

  • 0
    TI__Mastermind 30000 points

    Hello April,

    Looking through your two .zip files, I am not sure which VBUS, D+, D- scope captures go with the CTLx scope captures. Would you be able to compile them together in a power point or something so that I can easily look at all the relevant captures at the same time?

  • 0 in reply to Adam Mc Gaffin
    TI__Intellectual 830 points

    Hi Adam,

          The dongle is C to A.   Waveform has been combined as below. Pleas help to check. Any concern or problem, please let me know. This is an urgent case. 8867.waveform.pptx

  • 0 in reply to Adam Mc Gaffin
    TI__Intellectual 830 points

    Hi Adam,

          The dongle is C to A.   Waveform has been combined as below. Pleas help to check. Any concern or problem, please let me know. This is an urgent case. 3872.waveform.pptx

  • 0 in reply to April Jiang
    TI__Mastermind 30000 points

    Hello April,

    I do see one potential issue. On slide two, for the "power off" capture, why is the voltage on CTL3 not 3.3V like the other CTL pins? This may be read as a value of 0 instead of 1. This would put the TPS2546 in a SDP (CTL1,2 = 1 CTL3 = 0) charging scheme instead of the DCP_Auto (CTL1,2,3 = 1). This would explain why the waveforms look different between the two.

    If you want the same charging scheme for all situations, recommend that you pull the CTL pins to the input supply to the TPS2546

  • 0 in reply to Adam Mc Gaffin
    TI__Intellectual 830 points

    Hi   Adam,

    Customer feedback the board they capture waveforms is broken, and the waveform we reviewed is not correct. Today they use a board with no issue and capture the waveform again. Issue is still there, but CTL1, 2 3 performance is not same. Please refer to this attachment.  Please note, when we use a loading tool and test, no issue.

    Samsung product in close status,  Charging current 0.5A.

     Samsung product in open status, charging current 1.5A.

     7457.waveform.pptx

    Customer tried to SET CTL1,2,3 to 101, and in DCP mode, current is ok. But DCP mode could not transfer DATA. Just for your reference. Please help to check.

    Any concern or problem, please let me know. Thanks.

  • 0 in reply to Adam Mc Gaffin
    TI__Intellectual 830 points

    Hi   Adam,

    Customer feedback the board they capture waveforms is broken, and the waveform we reviewed is not correct. Today they use a board with no issue and capture the waveform again. Issue is still there, but CTL1, 2 3 performance is not same. Please refer to this attachment.  Please note, when we use a loading tool and test, no issue.

    Samsung product in close status,  Charging current 0.5A.

     Samsung product in open status, charging current 1.5A.

     62053.waveform.pptx

    Customer tried to SET CTL1,2,3 to 101, and in DCP mode, current is ok. But DCP mode could not transfer DATA. Just for your reference. Please help to check.

    Any concern or problem, please let me know. Thanks.

  • 0 in reply to Adam Mc Gaffin
    TI__Intellectual 830 points

    Hi   Adam,

    Customer feedback the board they capture waveforms is broken, and the waveform we reviewed is not correct. Today they use a board with no issue and capture the waveform again. Issue is still there, but CTL1, 2 3 performance is not same. Please refer to this attachment.  Please note, when we use a loading tool and test, no issue.

    Samsung product in close status,  Charging current 0.5A.

     Samsung product in open status, charging current 1.5A.

     8863.waveform.pptx

    Customer tried to SET CTL1,2,3 to 101, and in DCP mode, current is ok. But DCP mode could not transfer DATA. Just for your reference. Please help to check.

    Any concern or problem, please let me know. Thanks.

  • 0 in reply to April Jiang
    TI__Intellectual 830 points

    Hi Adam,

        Any update?

        Thanks.

    3034.waveform.pptx

  • 0 in reply to April Jiang
    TI__Mastermind 30000 points

    Hi April,

    Apologies for the late reply. Thank you for the clarification of the failing board sending the updated captures. I believe this is expected behavior, and what you are seeing is the CDP-SDP auto switch functionality of the TPS2546. This functionality is explained in the datasheet, but I've also included it in the capture below.

    Summary is that when the TPS2546 is configured to be in CDP mode, it will automatically switch to SDP charging if the connected device does not follow he proper enumeration for CDP charging. In this case, when the Samsung phone is closed, it does not follow the CDP charging scheme, so the TPS2546 automatically switches to SDP so that the phone can be charged as well as transfer data. When the TPS2546 changes charging schemes, it must dissipate VBUS, which is why you see a drop on VBUS between the two.

    This is expected behavior and is not an issue. Let me know if you have any other questions