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TPS65987DDJ: the measurement result show that VIN_3V3 is not higher priority, why?

Frank(EP) Liu
Expert 4870 points
Part Number: TPS65987DDJ


hi,

from datasheet 8.3.2.3, when both VBUS or Vin_3v3 are present, 987D will get the power from VIN_3V3.

below is the test condition:

monitor, ADCIN1 of 987d is 0.33(BP_ECWait_Internal).

type C port is power sink.

measurement result:

test 1:

1.plug in TypeC, vbus =5V, 8.54mA = 0.0427W

2. plug in adaptor(power meter shows 0.19W), vbus =5V, 8.54mA = 0.0427W

=> the type c power is from VBUS, why?

3. remove type c, adaptor(power meter shows 0.22W)

=> the type c power is from VIN_3V3

4. plug in type c again, vbus =5V, 0.08mA

test 2:

1. plug in adaptor (power meter shows 0.22W)

=> the type c power is from VIN_3V3

2. plug in Type C, vbus =5V, 0.08mA

it seems that the power is from VBUS or VIN_3V3 which is present first, not VIN3V3 has higher priority.

something wrong in my test?

BR,

frank

    

  • 0
    TI__Mastermind 29755 points

    Hi Frank,

    Can you see what's the Power Source bit in Power Path Status (0x26) register indicates before and after you plug in the power adaptor?

    I checked on my setup and the power source value changed to VIN3V3 when adaptor is plugged in.

    If you have your pjt file, please send it to me also.

    Regards,

    Peter

  • 0 in reply to pdjuandi
    TI__Expert 4870 points

    hi Peter,

    I use 987DDH evm test with attached project.D1104 Type C 20201116-2.pjt

    the reading for 0x26 for power source. 

    *******Switch 4 On only --> BP_WaitFor3V3_Internal (0.24)*****

    test 1:

    1.plug in TypeC, vbus =5V, 8.54mA = 0.0427W

    2. plug in adaptor(power meter shows 0.19W), vbus =5V, 8.54mA = 0.0427W

    => the type c power is from VBUS, why?

    3. remove type c, adaptor(power meter shows 0.22W)

    => the type c power is from VIN_3V3

    4. plug in type c again, vbus =5V, 0.08mA

    if I change the ADCIN1 to "Switch 4-6 Off --> BP_NoResponse (0)", the reading status is as spec.

    so, when ADCIN1 is "Switch 4 On only --> BP_WaitFor3V3_Internal (0.24)", the power source would be the one which plug in first?

    BR,

    frank

  • 0 in reply to Frank(EP) Liu
    TI__Mastermind 29755 points

    Hi Frank,

    Your attachment doesn't go through, but I think I understand what you are seeing.

    When you set ADCIN1 to BP_WaitFor3V3_Internal, the dead battery flag is still high thus it's using VBUS power source. You will need to clear the dead battery flag either by DBfg command or GPIO Barrel_Jack_Event to power from VIN3V3.

    Regards,

    Peter