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TPS659037: Using the part with an external embedded controller

Petr Belyayev
Prodigy 10 points
Part Number: TPS659037

Greetings.

I'm investigating whether an external embedded controller can arbitrarily turn the rails on and off as well as set Vout and other VR parameters via I2C/SPI writes. That would effectively mean overriding OTP-programmed state transitions and ideally ignoring the OTP as much as possible. Will that work?

Thank you.

  • 0
    TI__Expert 6700 points

    Hello,

    After the device is powered up, you are able to adjust the various regulator voltages via SPI as well as turn said rails on/off.

    Once the device is power-cycled again, however, the part will return to the default OTP states. It is not possible to change things like power-up sequencing, etc. once the OTP is already programmed.

    Regards,

    Alex

  • 0 in reply to Alex Saenz
    Prodigy 10 points

    Hi Alex,

    Thank you for your reply. Is that correct to assume that the power-up sequence can be effectively overriden regardless of what we have in the OTP?
    What I'm thinking of is:

    1. Set MODE_ACTIVE bits of SMPS/LDO control registers to OFF (which is default)
    2. MCU then initiates OFF -> ACTIVE transition by whichever means (GPIO toggling, register accesses etc.)
    3. Once the transition is complete all the regulators are in ACTIVE mode and are OFF due to their settings (we do not care much about the actual sequence at this point since all the regulators are OFF)
    4. The MCU accesses VSEL bits of LDOs/SMPS to set some voltage before enabling the regulators
    4. The MCU accesses MODE_ACTIVE in SMPS/LDO control registers to actually turn them on/off

    Thanks.

  • 0 in reply to Petr Belyayev
    TI__Expert 6700 points

    Hi Petr,

    Let me take a look into this a bit more. I should be able to have an answer for you later today (tomorrow at the latest).

    Regards,

    Alex

  • 0 in reply to Alex Saenz
    TI__Expert 6700 points

    Hi Petr,

    Can you send me the full part number for this device?

    Can you also let me know what the part normally does upon powerup prior to trying any of this? Which regulators come up and in what order?

    Regards,

    Alex

  • 0 in reply to Alex Saenz
    Prodigy 10 points

    Hi Alex,

    The exact MPN is TPS6590379ZWSR. The power up sequence has not been observed as of yet but it is generally expected to behave as per OTP setting (figure 9 in https://www.ti.com/lit/ug/sliu011f/sliu011f.pdf). The question in general is rather about how flexible it can be.

    Thanks.

  • 0 in reply to Petr Belyayev
    TI__Expert 6700 points

    Hi Petr,

    Changing the MODE_ACTIVE bit in the register after the device is powered on and communicating will not permanently change its setting. The powerup sequence, therefore, is not able to be altered. However the device starts up when it is first received is how it will remain.

    It looks like with the exception of maybe SMPS7 and SMPS9 all other MODE_ACTIVE settings for your device are set to PWM mode so all other regulators should powerup when going from OFF --> ACTIVE.

    Regards,

    Alex

  • 0 in reply to Alex Saenz
    Prodigy 10 points

    Hi Alex,

    Thank you for your support and assistance. I have one final question before having the matter settled.

    - Based on TPS659037 Register Map (Rev. B) every SMPSx_CTRL register has reset value of 0h (in is literally said that reset = 0h).

    - At the same time for every register that gets it's value from OTP the following is true:
    > A bit reset value of 0bX indicates that the bit value is coming from the OTP memory.

    The question is: does that mean that MODE_ACTIVE bits are zero at reset and are not affected by the OTP contents in any way?

    Thank you.

  • 0 in reply to Petr Belyayev
    TI__Mastermind 23655 points

    Hi Petr, 

    Thanks for reaching out! Our customer support team is unavailable Monday and Tuesday October 17-18th due to all-day workshops. Please expect a delayed response. Thank you for your patience.

    Regards,

    Garrett

  • +1 in reply to Petr Belyayev
    TI__Expert 6700 points

    Hi Petr,

    The MODE_ACTIVE bits are zero by default before the OTP is programmed. Once the OTP is programmed, the OTP configuration determines what the MODE_ACTIVE bit for each regulator is. When the spec. says "reset=0h" or "bit is set to 0 by default", that is referring to its setting before the OTP is programmed. Based on you part's OTP configuration, only SMPS7 and SMPS9 have their MODE_ACTIVE bits programmed to zero. All other MODE_ACTIVE bits are enabling the various regulators. This should be evident on powerup. The device will always powerup the same way so even if those bits are set to zero in active mode, as soon as the part goes from OFF-->ACTIVE, the MODE_ACTIVE bits will get set back to 1 and the rails will powerup again.

    Regards,

    Alex