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AM5716: emmc power supply 3.3v to 1.8v issue

Semon Zhang
Expert 8601 points
Part Number: AM5716

Tool/software:

customer AM5716 emmc sub-system originally use 3.3V power supply, due to the new requirement to adapt to the higher ambient operating temperature of the product, the power supply will change to 1.8V with optimized emmc card.

the PMU on the HW board is TPS6590379ZWSR, 

following is the power supply design:

please help check how to implement it in current design

Thanks

  Semon

  • 0
    TI__Guru 54422 points

    Semon,  Please make a proposal and we can review.

    Regards,

    Kyle

  • 0 in reply to kcastille
    TI__Expert 8601 points
    kcastille said:
    Semon,  Please make a proposal and we can review.

    Hi Kyle

        customer give following proposal solution:

        1. TPS6590379ZWSR provide 1.8V out form LDO4

            

        2. AM5716 vddshv11 power supply:

            

         3. emmc card power supply

            

      

        please help review customer power supply design above for emmc 1.8v solution

    Regards

       Semon

  • 0 in reply to Semon Zhang
    TI__Guru 52265 points

    Changing VDDSHV11 to 1.8V is correct, and changing the eMMC VCCQ pins to same 1.8V sis correct.  My concern would be the LDO4 current capacity (200mA).  The other connectors for LDO4 are not shown, but assuming similar to TI design it sources several analog rails on processor.  VDDSHV11 and VCCQ are digital IO pins, so not as sensitive to noise - maybe considered sourcing from V1_8D.

    Also ensure pullup on MMC signals are to correct supply (same 1.8V as VDDSHV11 and VCCQ)

  • 0 in reply to Robert Eschler
    TI__Expert 8601 points
    Robert Eschler said:

    Changing VDDSHV11 to 1.8V is correct, and changing the eMMC VCCQ pins to same 1.8V sis correct.  My concern would be the LDO4 current capacity (200mA).  The other connectors for LDO4 are not shown, but assuming similar to TI design it sources several analog rails on processor.  VDDSHV11 and VCCQ are digital IO pins, so not as sensitive to noise - maybe considered sourcing from V1_8D.

    Also ensure pullup on MMC signals are to correct supply (same 1.8V as VDDSHV11 and VCCQ)

    Hi Robert

        customer is also concerning the current capacity, 

       is there a recommended emmc 1.8V design for customer?

    Thanks

       Semon

  • 0 in reply to Semon Zhang
    TI__Guru 52265 points

    I'm attaching a similar processor EVM design (same processor package, similar functionality) - you can see how power supply for 1.8V eMMC is implemented (combined with other 1.8V rails).  That is why I recommend combine with V1_8D on TI's AM571x EVM design.

    517502C1_J6ECO_02MAR2016.pdf

  • 0 in reply to Robert Eschler
    TI__Expert 8601 points
    Robert Eschler said:
    I'm attaching a similar processor EVM design (same processor package, similar functionality) - you can see how power supply for 1.8V eMMC is implemented (combined with other 1.8V rails).  That is why I recommend combine with V1_8D on TI's AM571x EVM design.

    HI Robert

       Customer complete their emmc power supply design, please help review following schematics:

       --------------------------------------------------

    1.8V eMMC power supply solution，using original VCCQ 3.3V power supply V3_3D, through a LDO to output 1.8V，to supply power to VCCQ，the maximum output current satisfys ICCQ requirement.

    2. 

    3.

    4. 

    5. 

    6.

    ------------------------------------------

    Thanks

        Semon

  • 0 in reply to Semon Zhang
    TI__Guru 52265 points

    I don't see any issue.