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TPS659037: Operating without OTP power sequence and embedded power controller?

Anton Samuel
Prodigy 30 points
Part Number: TPS659037
Other Parts Discussed in Thread: TPS22976

Hi,

I have a separate low power always on microcontroller connected to TPS659037 PMIC via I2C. PMIC powers other chips: FPGA, DDR etc.
My FPGA requires 1.0V/0.85V instead of OTP default 1.15V and I would like to supply up to 9A from triple phase SMPS.

Is there a possibly to use PMIC avoiding the OTP EPC controlled power sequences and instead maunally implement them by using my microcontroller? Any limitations in this approach?

Basically, can I start the PMIC so that it does not provide any output voltages but has I2C registers accessible?

What do I have to do to avoid accidental OTP power sequence activation? Connect power on pin and some other configuration pins to gound/VCC?

Best regards,

Anton Samuel

  • 0
    TI__Mastermind 30280 points

    Anton,

    I have assigned this question to the experts on this device. It is possible you will receive a response before end-of-day today U.S. time, but please be patient if there is not a reply until Monday Jan. 11th.

  • 0
    TI__Mastermind 26650 points

    Hello,

    Do you mean you need 2 separates rails: 1V@9A and 0.85V@9A .

    Do you want these 2 rails start at 0V and ramp to 1V and 0.85V at power up?

    Regards

  • 0 in reply to Mahmoud Harmouch
    Prodigy 30 points

    Hi,

    No, I need just a single main rail that is configurable to be between 0.85V...1.0V dependin on the FPGA model.

    Yes, I want all rails to start at 0V since I need different configration from the OTP default.

    Best regards,

    Anton

  • 0 in reply to Anton Samuel
    TI__Mastermind 26650 points

    Hello,

    Any SMPS rail can be adjusted from 0.7V to 1.6V with 10mV step or 1V to 3.3V with 20mV step.

    Regards

  • 0 in reply to Mahmoud Harmouch
    Prodigy 30 points

    Hi,

    I have been extensively reading all documents that I can find about TPS659037, so I know that the voltages can be adjusted when the device is in active state.

    My questions are about device startup and avoiding activating the OTP defined voltages.

    1) Can you confirm that the I2C interface is available and active before OFF2ACT sequence is issued? I haven't found information about it.
    Because, if I2C is not active before OFF2ACT, I can't adjust the OTP defined startup voltages.
    The reason I am asking is because I have found a regsiter map document that very briefly mentions I2C access in SLEEP mode and RC15MHZ oscillator that can be turned on/off.
    "RC15MHZ oscillator is OFF in SLEEP mode. Minimize consumption in SLEEP mode (default)" and when turned ON "It allow to make I2C/SPI access in SLEEP mode." This is the only document that only once mentions RC15MHZ oscillator which seems to be required for I2C?

    2) If I2C is available, what precautions do I have to follow to avoid OTP default values becoming active at any point of time (later on)? Ie avoiding reset? Avoiding ACT2OFF, OFF2ACT?

    3) Default values for SMPS12 and SMPS3 are 1.15 and 1.35 respectively. I can't even connect them together in the schematics to build a triple phase system if there is any risk of supplying OTP default voltages for any period of time. What I need is 1.0V. I can't supply 1.35V to the FPGA and adjust it later on.


    Finally, if I can't use the I2C interface before OFF2ACT and/or if there is any risk that OTP values will become active despite overwriting them via I2C,
    the only solution that I can think about is following: I could put TPS22976 load switches at the output of every SMPS.

    Best regards,

    Anton

  • 0 in reply to Anton Samuel
    TI__Mastermind 26650 points

    Hello Anton,

    Thank you for the detailed explanation! the OTP has to be executed first before writing to I2C. The solution for your case should be external.

    Regards