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TPS65987D: tps65987D

Part Number: TPS65987D
Other Parts Discussed in Thread: TPS65987,

In my design I am using the TPS65987D as a DFP provide power.

I am using GPIO#14 as a push pull GPIO to turn on and off the power supply. I am using GPIO#15 as an open drain output (no internal pull or pull down). 

GPIO#14 is configured to turn on on a Port 0 plug event. This is working. When the UFP device USB-C cable is plugged in, GPIO#14 turns on as expected.

I configured GPIO#15  to turn on "port 0 PDO 1 Negotiated" event. This is not working. The open drain output seems to be turned on straight away i.e. not waiting for the PDO1 from the UFP device.

I need help fast. 

Thanks.

-Arif

  • Hi Arif,

    Could you please provide your GUI PRJ and the related schematic to me, I can verify it on our EVM.

    Best Regards,

    Kevin 

  • Hello Kevin,

    Here are the schematics and the configuration proj file.

    I need the GPIO#15/GPIO#17/GPIO#20 to be pure open drain outputs and turn on when Port 0 Source PDO 1/2/3 is negotiated (i.e. 9V/15V/20V load is requested). 

    Thanks for your help.

    Arif Khan

    302-0031-01.pdf302-0030-01.pdfcms_2.pjt

  • Hi Arif Khan,

    I will verify it on our EVM, and will get back to you soon.

    Kevin

  • Hello Kevin,

    Did you have new information? I would think it would be straight forward to put the GPIO outputs in open-drain mode and upon the receipt of the PDO message, the part would assert the output low to ground.

    I played with all different combinations in the GUI application customization tool and nothing seemed to have worked.

    Thanks

    -Arif

  • Hi Arif,

    sorry for late reply. First, we don't recommond directly use GPIO open-drain to pull to GND as you use, the long dsitance GND between the buck and TPS65987D will affect the FB adjustment accuracy, and at start up, TPS65987 need time to set the GPIO to open-drain, so it needs power on TPS65987 eariler than the BUCK.

    Back to your question, set the GPIO polarity to invert event can solve it.

    Best Regards,

    Kevin

    If this answers your question, Please click "This resolved my issue" button.

  • Kevin,

    I tried what you showed above. It is not working. GPIO#15 is getting enabled low and the switching regulator 9V is turning on immediately! 

  • Hi Arif khan,

    Could you capture the PD cc line trace ? i am not sure if the 9V is right response without the PD trace.

    Best Regards,

    Kevin

    If this answers your question, Please click "This resolved my issue" button.

  • Hi Arif khan,

    I suggest you to test the impedance of the GPIOs, when power on, no device insert. I have verify that on EVM board, the open-drain function is ok, when no device insert, the impedance is around 34Mohm, when Negotiated, the related GPIO impedance is around 20 ohm.

    Best Regards,

    Kevin

    If this answers your question, Please click "This resolved my issue" button.

  • Kevin,

    Can I get your project file so I can see your setup please?

    Thanks.

    -Arif

  • Hi Arif,

    i used your project, just change the GPIO 14 to port 0 source PDO 0 negotiated, disable the GPIO 15, configurate GPIO 2 to port 0 source PDO 1 negotiated(open-drain, invert event), GPIO 2 is more easily to test on EVM. Then i connect a smart phone, which can request 9V PDO, then use the multimeter test the impedance of this GPIO, i can see the impendance change of it.

    cms_TI.pjt

    Kevin

  • Kevin,

    Thanks for the info. So you did not test GPIO15, GPIO17 and GPIO20. These are the ones I am using to control the switching regulator.  

    I tried one more experiment. I disabled GPIO15,GPIO17 and GPIO20 in my configuration and only enable GPIO14 on port 0 plug event. In this scenario when I plug in a load, GPIO14 turns on and turns on the 5V. The system is working fine.  No conflicts. The other 3 GPIOs remain tristated and my board is working.  

    This tells me that your configuration software is not working and the design is fine. 

    Please send me the firmware source code for the micro controller inside the TPS65987D. I will debug this myself. 

    I need to resolve this quickly, my customer is waiting for this product.

    Thanks

    -Arif

  • Hello Kevin,

    Thanks for the info.

    But you did not try to make the GPIO15/GPIO17 and GPIO20 go into open drain mode. These are the pins which are not going into open drain mode!

    I am not interested about GPIO1 and GPIO2. 

    In my design, if I disable GPIO15/17/20, then the 5V turns on on a port 0 plug event. That means the GPIO15/17/ and 20 are being tristated by the firmware. If I enable any one or more of the GPIO15/17 and 20 pins, the firmware drives these pins low, and my design is not working. 

    You have a bug in your firmware!!!

    Thanks

    -Arif

     

  • Hi Arif,

    I know what you are setting, I just use the GPIO 2 to verify the setting I proposaled works, the GPIO15/17/20 has been mapped to other function and has other component connect to it, so it's not feasible for me to verify GPIO15/17/20 on EVM board. it should be more easy for you to verify it on your board, remove R15,R16,R17, connect a 9V PDO device, make sure "port 0 PDO 1 Negotiated" form the PD loag. Then see the implendance change of the GPIO15.

    Kevin

  • Hi Arif,

    What's verision you are using, TPS65987DDJ or TPS65987DDH ? Today, i get a chance to test it on TPS65987DDH EVM board, the GPIOs seem doesn't work under open-drain output type. Could you please use TPS65987DDJ for you project, i will report this issues to our FW team to analysis.

    Kevin

  • Hello Kevin,

    When do you think your ROM team will fix the code for the TPS65987DDH device ? i.e. the open drain issue?

    Thanks

  • Hi Arif,

    it depends on the bandwidth of FW team, it may take couple of weeks, I will inform you once they fix it. If your project is urgent, i suggest you use TPS65987DDJ, it is Pin to Pin with TPS65987DDH, and has no different on charging function.

    Best Regsrds,

    Kevin