• Resolved

TPS65987D: What settings to make sink compatible with old school 5V charger too?

Intellectual 705 points

Replies: 5

Views: 39

Part Number: TPS65987D

Hi,

I'm looking to see what setting adjustment I need to get the TPS65987D able to charge from either a USB PD source or an old school 5V charger.

I currently have the device charging at 45W at the highest power possible from the PD source, but a user may only have an older charger. 

The device is also configured as a DRP to allow it to act as a source if some other devices are inserted.  Hopefully that does not impact this need.

Thanks,

Chris

  • Hello Chris,

    It should work with Legacy chargers. You must be using Type A to Type C cable for connecting to a Legacy Type A port. This kind of cable has Rp pull up resistor connected b/w CC and Vbus, so TPS65987D should work as Type C sink. 

    If you are facing any issue, please share the scope trace of CC and Vbus lines. 

    Thank You.

  • In reply to Prajith Cheerakkoda:

    Hello Chris

    Please close this thread if you don't have further queries.

    Thanks

    Prajith

  • In reply to Prajith Cheerakkoda:

    From what I can see the issues seem to be related to the TPS chip not having a good value for allowable current which then gets relayed to the MSP micro and then confuses it so that it doesn't charge properly.  I'll take a look at that portion of the code and see if there is a fall back option I can use for allowable current when there is not a USB-C PD connection,

  • In reply to Chris Smith:

    Hi Chris,

    I did not get your point, I'm not able to see this issue on EVM. it would be helpful if you can provide more information.

    Thanks
    Prajtih

  • In reply to Chris Smith:

    This was in fact the issue.  The 0x34 negotiated contract allowable current was zero and so the charger was not going.  I implemented a if statement that if the mode is charging but the limit is zero to use 500mA and now it is fine on those types of chargers.

    Thanks!

    Chris