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TPS6594-Q1: using VIO_IN at 1.8V

SH
Intellectual 390 points
Part Number: TPS6594-Q1
Other Parts Discussed in Thread: J784S4XEVM

Tool/software:

What is the recommended powering scheme in case of powering the PMIC VIO from 1.8V?

For example,

Assuming the default PMIC NVM, can 1.8V VIO be taken from the PMIC BUCK4 regulator that is providing the 1.8V to the processor, or is a discrete regulator, that is powered on as soon as the PMIC input voltages (VCCA, PVINx) are on required?

  • 0
    TI__Genius 16700 points

    Hello, 

    Can you let me know what PMIC part number and the attached MPU are you talking about in this case? 

    Regards,

    Ishtiaque 

  • 0 in reply to Ishtiaque Panhwar
    Intellectual 390 points

    Using the PMIC TPS6594133ARWERQ1 with TDA4VH88TGAALYRQ1.

  • 0 in reply to SH
    TI__Genius 16700 points

    Hi,

    Thanks for sharing the information. 

    I do not think you can use BUCK4 output as VIO input. It may have impact due to sequencing and error handling operation. 

    The recommended is to use supply from VCCA_3V3  (see link of J784s4xEVM design; https://www.ti.com/tool/J784S4XEVM ). So that VIO should be available during the same time as VCCA. In  TPS6594133ARWERQ1 the VIO can be provided either in 3.3V and 1.8V. So now it depends on what is your input here in this case, if the VCCA is not 3.3V then you can use voltage divider circuit from VCCA and provide 3.3 V VIO or 1.8V from 3.3V but if the input is 3.3V then you basically do not need to use 1.8V.  

    Regards,

    Ishtiaque 

  • 0 in reply to Ishtiaque Panhwar
    Intellectual 390 points

    Thank you.

    Couple of follow up questions still on this:

    Could you elaborate that what kind of problems could this have for the sequencing?
    In the processor specification (document SPRSP79B) for the Power Supply Sequencing (Chapters 6.10.2.2 and 6.10.2.4) the 1.8V voltages are the second ones to ramp up after 3.3V. With the default shipped PMIC NVM, are some of the PMIC GPIOs used during the power sequencing before 1.8V ramps up?

    Instead of using the BUCK4 would there be any other 1.8V regulator output that could then be recommended to power the VIO_IN if wish to supply it from 1.8V instead of 3.3V? I see there is another thread on similar question where powering VIO_N from 1.8V is suggested to be possible ((+) TPS6594-Q1: Internal LDO to supply GPIO voltage VIO_IN - Power management forum - Power management - TI E2E support forums)

    Also, since PMIC datasheet is referring an option to power VIO_N from 1.8V, in what kind of setup has TI validated this usage? Has this setup been the voltage divider solution?

  • 0 in reply to SH
    TI__Genius 16700 points

    Hi,

    Exactly  for  same reasons mentioned in the referenced E2E I said that there could be issues. As said in the thread, you need to take things in account. Below is the user guide of TPS6594133ARWERQ1 with TDA4VH88TGAALYRQ1 and you can refer the power up sequences. Depends on whether you are landing in MCU after startup or in ACTIVE state. VIO should be available early enough for the any GPIO resource to work so that's why detailed consideration needs to be taken from all respects. Below user guide has all the NVM sequences and you can review those. 

    https://www.ti.com/lit/ug/slvuci2/slvuci2.pdf?ts=1741704620883&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPS6594-Q1 

    Regarding, TI validation, I do not remember of any use case with 1.8V but TI has used from VCCA (3.3V) that I shared the link of EVM schematic in my earlier reply. 

    Regards,

    Ishtiaque 

  • 0 in reply to Ishtiaque Panhwar
    TI__Genius 16700 points

    Hi,

    Exactly  for  same reasons mentioned in the referenced E2E I said that there could be issues. As said in the thread, you need to take things in account. Below is the user guide of TPS6594133ARWERQ1 with TDA4VH88TGAALYRQ1 and you can refer the power up sequences. Depends on whether you are landing in MCU after startup or in ACTIVE state. VIO should be available early enough for the any GPIO resource to work so that's why detailed consideration needs to be taken from all respects. Below user guide has all the NVM sequences and you can review those. 

    https://www.ti.com/lit/ug/slvuci2/slvuci2.pdf?ts=1741704620883&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPS6594-Q1 

    Regarding, TI validation, I do not remember of any use case with 1.8V but TI has used from VCCA (3.3V) that I shared the link of EVM schematic in my earlier reply. 

    Regards,

    Ishtiaque