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TPS25751: Power supply and power receiving do not switch.

Ryu Yamashita
Genius 3665 points
Part Number: TPS25751

Tool/software:

Hi team,

I am using a TPS25751 evaluation board for verification, and I am feeding power from J2 by connecting a tablet to J3 and routing it as shown in the following figure.
After making it receive power from the tablet with J2 unconnected, it does not shift to the operation of receiving power from J2 even if power is connected to J2.
Is there any possible cause for this?
Or if there is a method, please let me know.

Best Regards,
Ryu.

  • +1
    TI__Mastermind 34256 points

    Hi Ryu, 

    Ryu Yamashita said:
    After making it receive power from the tablet with J2 unconnected, it does not shift to the operation of receiving power from J2 even if power is connected to J2.

    If TPS25751 is first powered from J2 (VBUS), the device will boot up with the dead battery flag raised. When dead battery flag is raised, TPS25751 is unable to become the source until the DB flag is cleared. The DB flag can be cleared with two methods: 

    1. EC sending 4CC command "DBfg" which instructs TPS25751 to clear its dead battery flag 

    2. Configuring one of TPS25751 GPIO pins to be input event "Barrel_Jack_Event" and toggle the pin high. 

     If you're not intending to test dead battery flag, I recommend first powering the EVM through J3 port first and then connecting J2 port to the tablet. 

    Let me know if there's any questions or concerns!

    Thanks and Regards,

    Raymond Lin