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Original question:

TPS65220: PMIC Device failing to initiate power

TPS65220: TPS6522053RHBR Failed to generate power supply rails

Sharad Parekh
Prodigy 30 points
Part Number: TPS65220
Other Parts Discussed in Thread: AM6442, SK-AM64B

Tool/software:

Hello team,

We are facing issue with power-up sequence where PMIC GPO2 output is switching and BUCK2 (1.8V) is not gettng up.

I have attached the schematic with measured waveforms for your reference with voltage measurement at different points till Slot2. Currently we are using AM6442 SR2.0 SoC in our design.

Also, we have taken reference from SK-AM64B EVK board with use of eMMC instead of SD card.

Kindly check the same and let us know what could be the issue in power-up sequence?

Thank you

3364.Waveforms.zip  6087.Schematic.pdf

  • 0
    TI__Intellectual 2320 points

    Hi Sharad,

    Thank you for reaching out on e2e. 

    Looks like PMIC is trying to power up and sees a fault, goes to shutdown and trying to power up again and the cycle repeats.

    In the schematic i see the PMIC PGND (Pin33) is tied to GND but can you please check and confirm in the layout the powerpad of PMIC is solderdown onto the board?

    Sathish

  • 0 in reply to Sathish Vallamkonda
    Prodigy 30 points

    Hi Sathish,

    We have verified the PMIC IC PGND (Pin-33) soldering and it is been soldered properly.

    Please find the below X-ray image for your reference.

    From other e2e thread, we came to know that PMIC TPS6522053 production version requires >30uF capacitance on SW1/2/3 output. Do we require to change the capacitance accordingly.

    In our design, we have used 22uF capacitors as per SK AM64B evaluation kit. We also checked that pre-production version PMIC IC is soldered on EVK board. There are programming code change between pre-production and production version PMIC IC. Is it correct?

  • 0 in reply to Sharad Parekh
    TI__Genius 10270 points

    Hi Sharad,

    US in on public holiday 17th of Feb. They will come back to you next business day. 

    Br, Jari

  • 0 in reply to Sharad Parekh
    TI__Intellectual 2320 points

    Hi Sharad,

    That is correct, it requires min of 30uF for normal operation but would require lot more for better transient response, like 80uF.

    I see that Buck1 has even 10uF, which may not be sufficient for power up.

    Can you please try increasing all Buck out caps and see if it works?

    Also, is it possible to read PMIC registers 0x2B to 0x2F to see what fault is preventing PMIC to powerup?

    Sathish