This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65219: Questions on Powering the AM64x with the TPS65220 or TPS65219 PMIC application note

Genius 15970 points
Part Number: TPS65219
Other Parts Discussed in Thread: TPS65220, TPS51206, TPS22965

Hello,

My customer is considering to use AM64x with TPS65219.
Then they are checking " Powering the AM64x with the TPS65220 or TPS65219 PMIC" applicqation note (SLVAFE9).

Then they have some questions. There is the below block diagram on P16.

Q1. 

PVIN of TPS51206 is described as "From 3.3V-buck output".
But the PMIC doesn't have 3.3V output in this case.
Where this 3.3V comes from? Is it VSYS(3.3V) or TPS22965 output?

Q2.
Similar to Q1. Where the PVIN(3.3V) of TLV5518P comes from?

Q3
LDO1 and LDO2 outputs are not connected in this figure.
What does it mean? Are both outputs floating?

Regards,
Oba

  • Hi,

    Thanks for reaching out! Please find the responses below and let us know if you have any questions. Here's also the link to the TPS6521904 technical reference manual (TRM) which describes the default NVM register settings for this OPN. TPS6521904 Technical Reference Manual (Rev. A)

    PVIN of TPS51206 is described as "From 3.3V-buck output".
    But the PMIC doesn't have 3.3V output in this case.
    Where this 3.3V comes from? Is it VSYS(3.3V) or TPS22965 output?

    The VTT rail can be supplied by either, the 3.3V pre-regulator (VSYS) or the output of the external 3.3V power-switch. We recommend using the pre-regulator (VSYS) to make sure the maximum current of the external power-switch is not exceeded. 


    Q2.
    Similar to Q1. Where the PVIN(3.3V) of TLV5518P comes from?

    We recommend supplying the VPP rail with the 3.3V pre-regulator (VSYS). 


    Q3
    LDO1 and LDO2 outputs are not connected in this figure.
    What does it mean? Are both outputs floating?

    LDO1 and LDO2 are both free power resources (up to 400mA) that customers can use to supply any peripherals in their application. Since these rails are enabled by default, they still require the input and output caps even if they are unused. 

    Thanks,

    Brenda

  • Hello Brenda,

    Thanks for your reply.
    The 6521904 TRM document says that PVIN of TPS51206 and TLV75518P comes from the power switch output although it is AM62 not AM64.
    But you recommended to use VSYS. Is the power sequnce no problem on both case?

    Regards,
    Oba

  • Hi, 

    The external power-switch, when enabled by the PMIC_GPO2 is the first rail to turn-ON in the power-up sequence so there should not be any issues if the VTT and VPP rails are supplied by the VSYS pre-reg or the external power-switch.

    We recommend using the VSYS pre-reg because it has the same voltage (no increase on power dissipation) and it would reduce the risk of exceeding the maximum output current of the external power-switch. 

    Thanks,

    Brenda