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TPS650864: TPS650864: Power sequencing order & current requirement

Part Number: TPS650864
Other Parts Discussed in Thread: TPS544C25, CSD87331Q3D, PMP12004-HE, TPS650861, CSD87350Q5D, CSD87588N,

Hi,
Part No.:- TPS6508640, TPS544C25,CSD87381P1, CSD87331Q3D
Evaluation Board:- PMP12004-HE
FPGA:- XCZU9EG-FFVB1156

      i am using Xilinx "XCZU9EG-FFVB1156", for that trying to use "TPS6508640","TPS544C25" and PMP12004-HE
reference design. But reading the TI document getting few confusion. so requested to clarify the below point:-

1. As per Xilinx data sheet "VCCINT" should be powered up before "VCCBRAM", But as per TPS6508640 datasheet "VCCINT" getting
powered up later to "VCCBRAM". if we use the reference design as per TPS6508640, will it create any problem to FPGA while
power on and its functioning ?

2. please refer para 6.3 of "TPS6508640" datasheet saying that "Dashed lines show the option to short VCCINT with
VCCBRAM for cases where their voltages are the same and current < 25 A. In this case, the TPS544C25 device is not
needed and GPO1 should be shorted to CTL4". The suggested FET "CSD87381P1 (in TPS6508640 datasheet" " or "CSD87331Q3D (in PMP12004-HE)", having current rating max 15A.
then how to achieve the current requirement between ">20A and <25A" when "VCCINT" and "VCCBRAM" are shorted together.

3. as per xilinx dataseet (ug583, page no. 34, table no. 1-13), "VCC_PSPLL" power supply should be different then "VCC_PSAUX" power supply. but in "PMP12004-HE", both are
supplied by "BUCK 5". Also as per xilinx dataseet (ds925, page no. 4, table 2) recommanded voltage level for "VCC_PSPLL" is 1.2V while "VCC_PSAUX" is 1.8V, then
why both supply are coupled in "PMP12004-HE"?

4. Can we change the power sequence order in "TPS6508640" via I2C, permanentaly?

Thank You

  • Hi Alok,

    Thank you for reaching out. The most likely reason for the mismatch in sequencing & connection is changes in the processor requirements between the development of PMP12004-HE and now. It was developed very early in the ZU+ life cycle.

    The good thing is that you can use the user programmable TPS650861 to create any version of this design you would like. There is even a TPS6508640 example file which can be used as a starting point: 

    Regarding the BUCK2 current, as noted in Figure 6-3, the FETs should be scaled to account for the current. For higher currents, we generally recommend CSD87588N or CSD87350Q5D.

    Please let me know if you have any additional questions. 


  • Part No.:- TPS650861


    Hi Kevin,

    Thanks for replying. TPS650861 looks suitable for my design, but after studying the datasheet few confusion arises. So please help me regarding the below points:-

    1. What is the factory set value for (please mention each value):-
    BUC Controller 1
    BUC Controller 2
    BUC Convertor 3
    BUC Convertor 4
    BUC Convertor 5
    BUC Controller 6
    LDO A1
    LDO A2
    LDO A3
    SWA1
    SWB1
    SWB2
    VTT LDO


    2. The power sequence order shown in "figure 5-10 on page no 34" (TPS650861 datasheet), is the factory set value? Means may i achieve this sequencing
    initially without programming the PMIC in my design?

    3. I want hardware controlled "power on sequence" via "CTL" pins in my design. please tell me which VR group is assigned to
    which CTL pin by factory set. Also if i make any kind of hardware connection to my design, on "CTL" pins for power sequencing,
    then later will it be possible to change the power sequence order via I2C control, without changing any hardware control
    over "CTL" pins?


    Thank you.

  • Hi Alok,

    1. The TPS650861 is essentially blank, so factory set value for all voltages will be the minimum VID value (0x00) for all regulators and there will be no sequence. You can see the default values in the datasheet register map section if you'd like to double check.

    2. Figure 5-10 is an example of how you could program it; it happens to be the settings for the TPS650860RSKR orderable in that image. It is not what the device does already. 

    3. Using the OTP Generator you can create sequences using the CTL pins. The two links I provided in the last past describe how to do this. I also did a video a while back, but it doesn't cover as many of the details: https://training.ti.com/tps65086100-user-programming-multi-rail-power-management-ics

    One note: once programmed in, the sequences are locked. However, you can bypass the sequencer using the [Regulator]_EN and [Regulator]_DIS bits to manually control regulators. There are also two banks of OTP so you could potentially program the second bank if you only needed to change sequences once. 

    Once you have completed and tested your OTP Generator file, you can program units in production yourself or utilize a third party (both Arrow and Avnet have the capability currently) to program units.

  • Hi kevin,

        I am sorry, but i am not getting clear from the TPS6508640  datasheet. Can you reply/clarify below points:-

    1. In TPS6508640 datasheet  the timing diagram shown on page no. 25 is the factory set value for power sequence?

    2. As stated in datasheet for CTL pins that " A group of VRs can be assigned to be enabled at assertion or disabled at deassertion of this pin.", what is the factory set VR groups assigned to CTL1, CTL2, CTL3,CTL4,CTL5 and CTL6 ? Also which VR group PG is assigned to which GPO pins. Also how to assign a VR group to any CTL pins?

    3. on page no. 26, CTL pins function is defined. Is this CTL pins function is factory set?

    Thank you

  • Hi Alok,

    1. Correct, pg 25 shows the factory programmed power sequence for the TPS6508640 orderable.

    2. For a factory programmed device, assignment is done by TI and cannot be changed. The sequence indicates how they are assigned. For example, BUCK2 is enabled by CTL3, GPO1 is enabled by BUCK2_PG, etc. If you wanted to see the behind the scenes, it is in TPS65086100 OTP Generator for Xilinx Zynq Ultrscale+ (TPS6508640 settings). The TPS650861 orderables are programmable so you can change them.

    3. Correct.

    To be clear, the TPS650861 and TPS650864 are the same silicon, the TPS650864 is just the pre-programmed version. TPS650861 could be programmed to match the TPS6508640 if desired.