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Original question:

TPS25750: Single port Sink/Source solutions

TPS25750: Abnormal 18W Source with TPS25750EVM

Holly Gu
Intellectual 2750 points
Part Number: TPS25750
Other Parts Discussed in Thread: LM3489, BQ25713,

Hi Adam,

   I got TPS25750EVM and tested it. But met an issue need your help. The project file is as attached. 1122.SOURCE18W_SINK100W_TEMP.zip

1. Sink function is OK, I can see VBUS got a 20V voltage.

2. Source is not OK when charger a mobile phone.

1) D5, D6 and D10 are blinking. P3V3 = 3.3V, P5V = 5V, SYS_PWR = 20V.

2) The waveform of VBUS is as below, never negos to 9V, which is not correct.


3) The waveform of VAR_DCDC is as below, 

4) Use the same mobile phone + the same wire + TPS65988EVM, it's OK to get 9V@VBUS.

3. EVM HW set up are as below:

How to get 9V output as expected when acting as a source?

Thanks and Regards,

Holly

  • 0
    TI__Mastermind 30000 points

    Hi Holly,

    This is a know issue with this revision of the EVM and one that will be fixed for the next release of the EVM. sourcing 15V and 20V from the DCDC works as expected. Just the 9V source has issues. However, for the time being, this should help fix your issue.

    It is important to note to only use this setup when you want to evaluate the PD controller as a SOURCE. Do not connect a charger where the EVM will act as a power sink. 

    If you have access to an external bench supply, remove the header on J3, and connect a 9V supply to pin 2 of J3. When acting as a source, the TPS25750 is configured where the PP5V to VBUS power path will supply a 5V contract, while the PPHV to VBUS_IN will supply 9V, 15V, and 20V. So when the 5V contract is negotiated, the 5V DCDC on the EVM will supply this, then once a 9V contract is negotiated, the TPS25750 will close the PPHV to VBUS_IN power path, passing the 9V dedicated supply from PPHV to VBUS.

    Let me know if this fixes the issue or if you have any questions

  • 0 in reply to Adam Mc Gaffin
    TI__Intellectual 2750 points

    Hi Adam,

       I tried external 9V supply and the source function is normal now. May I know it is due to the buck LM3489 or the logic GPIO2/3 output from TPS25750? 

       And what's the schedule for next EVM release? Does that also support BQ25713 as you mentioned in the block diagram? 

  • 0 in reply to Holly Gu
    TI__Mastermind 30000 points

    Hello Holly, 

    We believe it is the slew rate of the LM3489 but we are not 100% sure. This is a copy and paste of the power architecture used for the TPS65988EVM, so we were surprised to see any issues with it. Once again, this will not be an issue with the new version of the EVM

    I shared the wrong block diagram, but I updated my previous post with the block diagram for the Rev E1 version of the TPS25750EVM, which is the one you currently have. 

    The BQ25713 will be implemented on he future builds of the TPS25750EVM so that customers can test the high voltage Source/Sink functionality dynamically