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  • TI Thinks Resolved

AM5706: Power sequencing

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Replies: 11

Views: 365

Part Number: AM5706

     I want to use two TPS65261 cascades to power the AM5706. the VDDSHV_1 to VDDSHV_11  are all 3.3V.The power-up sequence I want to achieve is VDDS_1V8-----VDA_PLL_1V8----VDD_DDR_1V35 -----VDD_CORE_AVS-----VDD_DSP_AVS---VDA_PHY_1V8-----VIO_3V3---ddr1_vref0(VTT_DDR)---H_PORz。

      therefore, VIO_3V3  which is  used to power  VDDSHV1~VDDSH11(including VDDSH8) is the last power for AM5706。And it is used to generate DDR1_VREF and  H_PORz. So i think the VDDR_VREFSTL(ddr1_vref0) is  too later away from VDDS_DDR1?  From the power up  sequence pic,ddr1_vref0 and VDD_DDR_1V35 should be in front of VDD_DSP_AVS and other power,but from the note below,it says  it just must be valid before porz rising ,not mention the relationship between ddr1_vref0 and VDD_DSP_AVS.

Besides  I Even doubt it(ddr1_vref0)may after(behind)H_PORz. Is my idea correct? Is there any good advice about this ddr1_vref0 power supply?  

       As you see  pic below ,Equivalent to putting ddr1_vref0 behind vddshv8 (3.3V, merged with other VDDSHX)。

       power.pdf

  • We can't support using any power management IC other than those in the datasheet. 

    These are the options:


    The PMICs we've selected support dual votlage SD cards and accelerated shutdowns via drain resistors that the TPS65261 don't appear to support. You'll have issues meeting the power down requirements. 

  • In reply to Ahmad_Rashed:

    If I don't care about its power-down sequence, let them lose power at the same time. What problems will this cause, will affect my second power-on, or will affect the life of the chip, or other problems.

  • In reply to user4973896:

    There are relationships between the supplies that need to be met otherwise there is a real risk of damaging the device. The AM57x device and the PMIC options were designed together so there are needs that can only be met with the PMIC.

  • In reply to Ahmad_Rashed:

    Hello,

    First,I would like to ask if the AM570X is powered,  TPS65916 and LP87332D + LP873220, which is more suitable for cost consideration?Which is main push  of TI ?

    Second ,about TPS22965QWDSGRQ1 and TLV62130RGT ,which chip is used in large quantities, the cost of which is lower, because our company is currently using TLV62130RGT more , i want to replace TPS22965QWDSGRQ1 by TLV62130RGT .but it seems TPS22965QWDSGRQ1 is cheaper to see the official website , please inform me huriiedly! Later i find  that i must use TLV62130RGT ,because my system input is 5V。

    Third,in design TIDA-01425,the VIN OF TPS51200  is SYS_3V3, but my system power is 5V。First,The 5V input,  through LP87332D and LP873220, generate various power supplies required by AM570X, and finally generate 3.3V through TLV62130. If this 3.3V is used to generate VDD_REF and VDDR_VTT, then the time between VDD_DDR_1V35 and VDD_DDR_1V35 will be too long. you know the vin  of TPS51200 MUST be 3.3V,SO I DON'T know use which vin to produce VDD_REF and VDDR_VTT ?

    Fouth,can i connect all the input of LP87332D + LP873220  together to my main power 5V, AND two En  of LP87332D + LP873220  directly to 5V(INPUT).

    FiFth,in the design TIDA-01425 ,R96 and R96 ,I see they are all populated,Why is this so there is no problem? Because I do not have sys——3v3,my system input power is 5V,so i should choose R97 POPULATED,RIGHT?

    Sixth,IN  “LP87332D and LP873220 User’s Guide to Power AM570x”  document ,it says  When system has only 3.3V rail available, VDDA_USB3V3 should be connected to 3.3V rail via load switch. LDO1 of LP87332D can be used as enable for the load switch. VDDA_USB3V3 means the pin AA10(VDDA3V_USB_1)and pin Y10(VDDA3V_USB_2) connected to the output of the switch TPS22965QWDSGRQ1, RIGHT?

    Seventh,https://e2e.ti.com/support/processors/f/791/p/717998/2647946?tisearch=e2e-sitesearch&keymatch=LP87332D%20EN%20%20AM570X#2647946,in this link,LP87332D + LP873220 is not recommended when VBUS detection or dual-voltage SD card are needed。What is VBUS detection ?

  • In reply to Ahmad_Rashed:

    hello,ahmad,can you  see  my   reply?

  • In reply to user4973896:

    1, 2, 3, 4) 

    For either solution it would be more power efficient to use a 3.3V system supply available first, this can be the TLV62130RGT if it fits in the power consumption requirements. Of the two it seems like LP87332D + LP873220 is the cheaper solution. The 3.3V system supply can then be used for the TPS51200 and fortunately you can use non-Q1 version of TPS22965 which should be cheaper.

    5) 

    It's not clear. However we always recommend checking the datasheet to meet recommended operating conditions. The datasheet takes precedence over our ti design or sitara EVM schematics.

    6)

    Yes the VDDA3V_USB_1/2 supplies on the SoC can be connected to the TPS22965 output. All 3.3V ICs in your system which communicate with the SoC must also be on this supply. 

  • In reply to user4973896:

    7)

    VBUS detection is used when the sysem is a USB client to a host PC. The PMIC detects the 5V bus voltage from an external system and sends an interrupt to the AM570x. Any open-drain buffer with 5V tolerant input can be used to toggle a GPIO on the SoC instead of the PMIC.

  • In reply to Ahmad_Rashed:

    First,Ahmad_Rashed ,Thank you very much for answering my question.!But Can you answer my questions one by one?Because there are problems I care about, you simply don’t answer

    I still have  a  question!

         My current solution is to use the 5V power supply to generate various power supplies through the LP87332D + LP873220. Then, when REGEN1 is active (the GPO of the LP87332D), the SW_3V3 power supply of the peripheral is generated by the TLV62130RGT, and finally the DDR_VREF and DDR_VTT are generated by the SW_3V3 through the TPS51200. Thus DDR_VREF will be generated between SW_3V3 and PORZ, which will be a long time away from VDD_DDR_1V35, but DDR_VREF will be generated immediately after VDD_DDR_1V35 on "LP87332D and LP873220 User's Guide to Power AM570x", will there be any problem?

    Ahmad_Rashed, can you answer faster?

  • In reply to user4973896:

    Using TLV62130 in place of TPS22965 will not work. 

  • In reply to Ahmad_Rashed:

    Why?Can you explain more detail!

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