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TPS659037 shuts off the the switchers after 8-12 sec

Amrendra Kumar
Intellectual 270 points
Other Parts Discussed in Thread: TPS659037, AM5728

We are using TPS659037 PMIC with AM5728 processor in our design. The switcher output of PMIC turns off after 8-sec. Then i changed the POWERHOLD pin as high.Now the PMIC shuts off it's switcher after 12sec. My default boot setting is [00].

How i can keep the TPS659037 ON always before we do any programming? As per datasheet "DEV_CTRL.DEV_ON" register need to be set ON to make device ON.

What is the hardware work around for keeping TPS659037 ON always? I pulled up POWERHOLD pin high, but this doesn't help.

Thanks

Amrendra

  • 0
    TI__Genius 16410 points
    Hello Amrendra,

    How are you connecting the PWRON signal? This signal can be held low to turn off the PMIC after 12 seconds (default). If this signal is always held low, this could be the issue.

    In case you are not using PWRON, it should be left floating or pulled up to VCC. Then setting POWERHOLD high will keep the PMIC on. Note that POWERHOLD and DEV_ON are used as an OR function to keep the PMIC on. Either one can be enabled to keep the PMIC on, but both need to be disabled to shut the PMIC off.

    Regards,
    Karl
  • 0 in reply to Karl Wallinger
    Intellectual 270 points

    Hi Karl

    yes after removing the pull-down on PWRON signal i am able to keep the power supply ON always.

    Now i am facing issue in setting voltage for SMPS7 and SMPS9. I have mounted the PMIC with option 0X7D and getting 0volt default when enabled get 3.3V. However tried setting different values in SMPS7 and SMPS9 register it still give me a output of either 0 or 3.3V. I need  to set 1.5V for SMPS7 and 1.2V for SMPS9.

    Is there any specific setting to set desired voltages? Do i need to follow any sequence. I am able to readback the values from  PMIC whatever is being set in voltage register.

    Thanks

    Amrendra

  • 0 in reply to Amrendra Kumar
    TI__Genius 16410 points

    Hello Amrendra,

    Would you be willing to share the schematic around SMPS7 or SMPS9 output?  It should be connected the same way as the other outputs.  If you are only getting 0V or 3.3V, you might check that the feedback signal is connected to the output correctly.

    I just checked on my EVM based on this question (maybe the same issue as yours?) and set SMPS7 to 1.5V with the following commands:

    I2C write: I2C address 0x58, register 0x33, data 0x6A

    I2C write: I2C address 0x58, register 0x30, data 0x03

    No other commands are needed, so I think there must be some other issue.

    Regards,
    Karl

  • 0 in reply to Karl Wallinger
    Intellectual 270 points
    Yes connection is in same way as other regulator. I can send snapshot of schematics , however don't see an option for attachment. Can you guide me how to send an attachment here.
  • 0 in reply to Amrendra Kumar
    TI__Genius 16410 points
    You might have to do "Use rich formatting", and then add attachment. Otherwise you can send my an e-mail using the address in my profile.

    Regards,
    Karl
  • 0 in reply to Karl Wallinger
    Intellectual 270 points

    Here goes the attachment