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USB PD battery status messaging question "eBatterySOC"

Ryo Akashi
Genius 9470 points
Other Parts Discussed in Thread: TPS65987

Hello experts,

I have question about USB PD battery status message.

In USB PD specification section9, there is command "eBatterySOC".

By utilizing "eBatterySOC", I want to check battery status via CC communication.
 e.g. check mobile battery(source) status from sink equipment via CC communication.
Does TI have USB PD solution which utilize "eBatterySOC"?
Also, if we want to know the battery status, using battery fuel gauge is only way?

Thanks and best regards,
Ryo Akashi
  • 0
    TI__Expert 5330 points

    Hello Akashi-san,

    TI has all of the pieces needed to meet your "eBattery SOC" requirement.  The TPS65987/8 USB PD controller can send and receive Battery Status messages, but an external uC needs to fill in the battery information.  Many of our chargers are able to provide status info via I2C such as to whether the battery is charging or discharging, but for specific details we would need to know the specific part number you would like to use.  As you said, a fuel gauge IC is the best way to get the state of charge information.

    To summarize, a uC reads the information needed to fill in the Battery Status Structure from a combination of charger and fuel gauge registers and then sends the BatteryStatus message using the TPS65987/8 USB PD controller.  For more information on the USB PD messaging, you may want to post a message to the USB PD power forum under the TPS65987 part number.

    Regards,

    Steve

  • 0 in reply to Steve Preissig
    TI__Genius 9470 points

    Hello Steve-san,

    Thank you very much for your reply, I'm sorry for my late reply.
    I understand TI's PD controller can send/receive battery status message, and uC and fuel gauge is needed to read actual battery information.

    Regarding this topic, let me ask some additional questions.

    1.
    Is the command "Get_Battery_Status" used on USB data line(D+/D-)? 
    Is it possible to send/receive "Get_Battery_Status" on CC line? 

    2.
    In USB specification, the command related with Battery status is described as "Shall".
    In generally, all battery which support Power Delivery support such command?
    If you know, I would appreciate if you would tell me.

    Thanks and best regards,
    Ryo Akashi
  • 0 in reply to Ryo Akashi
    TI__Expert 5330 points

    Hi Akashi-san,

    1.  The "Get_Battery_Status" USB PD message is only sent over the CC line.  I am not aware of any standard that supports sending this message over D+/D-.

    2.  I am afraid that I don't know the answer to this question.  I have worked with other customers who have implemented this support, so I know that at least some battery-powered PD systems do support this command, but I don't know what percentage of all the products in the market have implemented this.

    Regards,

    Steve