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TPS65987DDK: TPS65987DDH+BQ25723

Johnsin Tao
Intellectual 1625 points
Part Number: TPS65987DDK
Other Parts Discussed in Thread: BQ25723, TPS65987, TPS65987D

Hi   engineers:

     

I have built a fast charging circuit using TPS65987DDH + BQ25723, now it charges properly when negotiating 15V input using PD adapter; it does not charge at 20V input.

The charging voltage of the battery used is 8.4V, the PD adapter supports a maximum 65W output, and ADCIN1 DIV=0.91

The following problems were found during use:

1, When charging using 15V input, charging is only possible if the PD adapter is plugged in first to allow the TPS65987DDH to load the firmware image, and then the battery is connected. How do I modify the configuration so that I can connect the battery first and then the PD adapter for normal charging?

2、After starting charging according to question 1, the battery will stop charging in about 2~3 minutes (the watchdog of BQ25723 has been turned off). At this time, I quickly unplugged the PD adapter once again to continue charging until the battery is full. How to solve this problem and what is the cause of the problem?

3, at the same time also found in the use of PD negotiation 20V input BQ25723 can not be normal for battery charging, but 15V input can be normal according to the description of the problem 1 charging, charging set to 8.4V/3.5A. 20V input regardless of the setting of the charging current for 3.5A or 5A can not be charged at this time to test the BQ25723's VDDA = 6.069V, VSYS = 6.69V are normal.

The following files are the TPS65987DDH firmware and circuit diagrams that I used:

PD sink 15V:

7652.pd-change.pjt

PD sink 20V (BQ25723 not charging):

1376.1pd-change.pjt

Circuit diagram:

0728.PDtest.pdf

I would appreciate any help from experts to solve the above problem!

Thanks

Johnsin  Tao

  • 0
    TI__Genius 10740 points

    Would you mind clarifying what you are plugging and unplugging? Are your BQ25723 and TPS65987 chips on different boards? If so, what nets are being connected and disconnected? When you refer to your "PD Adapter", what are you referring to (USB-C cable plug, or something else)? When you refer to connecting and disconnecting the battery, are you literally connecting and disconnecting the battery terminals?

    I have an idea as to what your issue could be, but will need the above clarification to be certain.

    Kind regards,

    Conner Gillette

  • 0 in reply to Conner Gillette
    TI__Intellectual 1625 points

    Hi  engineer:

          Thank you for your reply, here is an additional description of my problem:
          1, the plug in question 2 is the PD adapter, i.e. the USB-C cable plug.
          2, BQ25723 and TPS65987 chip on the same board.
          3, "PD adapter" refers to the USB-C cable plug (which is connected to a charger that supports a maximum output of 65W).
          4, Yes, completely disconnect the battery from the board.
          I hope the above additional instructions will help you confirm my question.
    Thanks!

  • 0 in reply to Johnsin Tao
    TI__Genius 10740 points

    Are you able to confirm that your configuration is being loaded at all? If you switch your Default Device Configuration to "Infinite Wait" and your Dead Battery Configuration to "BP_NoResponse", you will only see power being sunk or sourced if your configuration is loaded, which would only occur when your battery has provided VIN_3V3 to the TPS65987.

    If you make these ADCIN1/SPI_POCI changes, and you do not see your configuration being loaded, I would check the voltage present at VIN_3V3 when your battery is connected to the board and no USB-C cable is plugged in.

    Kind regards,

    Conner Gillette

  • 0 in reply to Conner Gillette
    TI__Intellectual 1625 points

    HI

        I tried to change Dead Battery Configuration to BP_NoResponse by modifying ADCIN1, and then observed that: after plugging in the USB C plug, the 3V3_LDO has an output but the firmware is not loaded, and then after plugging in the battery, the TPS65987D can load the firmware and start charging.
    Then I tested and found that if I accessed the battery first and then connected the USB C plug, the BQ25723 did not work, the firmware could not be loaded and the battery did not charge. Same problem as mentioned at the beginning .
    Meanwhile, I also tested VIN_3V3 to the TPS65987, the voltage is normal 3.3V
    Best regards

    Thanks.

    Johnsin Tao

  • 0 in reply to Johnsin Tao
    TI__Genius 10740 points

    Would you be able to capture the I2C traffic? That will help me determine why the configuration isn't being loaded.

    Kind regards,

    Conner Gillette