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TPS65982: PD Reset due to VIN_3V3 Drop

Jim CHEN
Expert 4795 points
Part Number: TPS65982

Dear Team,

I got three different test results when testing TPS65982 EVM. And I used TPS65983A as its port partner. (firmware version 4.45)

Here are the firmware version I test:

1.12.06

1.11.09

1.07.00

My setup as below figure.

After the connection as above figure, I remove the adapter of 982 EVM. 

In 1.12.06, it set dead battery flag up, but its power source still shows VIN_3V3. There is nothing in PD log. VBUS didn't drop.

In 1.11.09, it didn't set dead battery flag up, but its power source still shows VIN_3V3. There is nothing in PD log. VBUS didn't drop.

In 1.07.00, it set dead battery flag up, and its power source is VBUS. In the log, PD issue HRESET to its port partner and negotiate again. VBUS drop.

I would like to know what would be the expected behavior for PD controller when VIN_3V3 drop.

Please help to clarify. Thanks.

  • 0
    TI__Mastermind 36756 points
    Hi Jim,

    Are you using the same configuration in all test cases? Only changing the low region image?
    The expected behavior would be as in 1.12.06, we would expect the VIN_3V3 to momentarily drop (Since you removed the barrel jack, this will set the dead battery flag.) The power path that you are sinking on then needs to come out of RCP and pass power through to the EVM. After the switch comes out of RCP, the VIN_3V3 supply on the EVM will come back up. The momentary loss of VIN_3V3 will set the dead battery flag since the TPS65982 will be momentarily be powered by the VBUS_LDO until the VIN_3V3 supply comes back up. Once the VIN_3V3 supply is back, the TPS65982 will draw power from there. The dead battery flag will not be cleared until the user clears it through the DBFg command.

    Thank you,
    Eric