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66AK2H14: Smart Reflex on 66AK2H14 EVM

joe lindula
Mastermind 6850 points
Part Number: 66AK2H14
Other Parts Discussed in Thread: UCD9244, , TPS53659, UCD9244-EP, LM10011, UCD74120, TPS544C25

Hello, I would like to get some more information on how implement the Smart Reflex on the 66AK2H14 processor. I have looked at the schematics for the EVM board and see that they use two UCD9244 devices page 40 and 41. I can understand page 40 but not page 41. On page 41 the UCD9244 has it VID pins tide to VCC3V3_AUX and I don't see how that is functioning as a Smart Reflex. Can some one clear that up for me and is this the only Smart Reflex implementation for the 66AK2H14? 

I have look at the Hardware Design Guide for KeyStone II Devices pages 10 - 14 and see other implementations of the Smart Reflex that see easier to understand than the 66AK2H14 EVM schematics. I think once I understand page 41 in the schematics things may be better understood. 

Thanks,

Joe

  • 0
    Mastermind 6850 points
    I just did a search on the UCD9244 and not they recommend to use the TPS53659.
  • 0 in reply to joe lindula
    Mastermind 6850 points
    Ooops, my typo. They don't recommend the UCD9244 for new designs. Sorry
  • 0 in reply to joe lindula
    Mastermind 6850 points
    The datasheet for the TPS53659 is very short and is lacking a block diagram. Has anyone used this device with the 66AK2H14?

    Thanks,
    Joe
  • 0 in reply to joe lindula
    Mastermind 6850 points
    I guess the UCD9244-EP is still available.
  • 0
    TI__Guru**** 161600 points
    Hi Joe,

    On page 41 the UCD9244 has it VID pins tide to VCC3V3_AUX and I don't see how that is functioning as a Smart Reflex. Can some one clear that up for me and is this the only Smart Reflex implementation for the 66AK2H14?


    Have a look at this thread:
    e2e.ti.com/.../562455
    It explains in details how the smart reflex is working on K2H. There are also other links in the above thread, that should be useful to you.

    No this is not the only way to implement the Smart Reflex for 66AK2H14 devices. See the bellow thread:

    e2e.ti.com/.../395850

    The answer from Bill contains a presentation from the power supply group describing analog controller solutions for the K2H using the LM10011 for AVS control. Of course the Hardware Design Guide for KeyStone II Devices is another source that can be followed to implement the Smart Reflex for KS2 devices.

    Hope this helps.

    Best Regards,
    Yordan
  • 0 in reply to Yordan Kovachev
    Mastermind 6850 points
    Yordan,

    Hello, I'm pouring over the documentation and I have learned that the VCNTLxNT pins (AU36, AV37, AV36, AU35, AW36) are now Reserved pins. Need to modify my schematic for that update. With that update can you please tell me what would I do with the inputs on the U16 (UCD9244) pins: 20.22,29, and 14 page 40?

    Last, this doesn't change anything on page 41 right?

    Thanks,
    Joe
  • 0 in reply to joe lindula
    TI__Guru**** 161600 points
    Hi,

    Sorry for the delay, I was OoO. I will look into this and update.

    Best Regards,
    Yordan
  • 0 in reply to Yordan Kovachev
    TI__Mastermind 46460 points

    Joe,

    The K2H EVM contains 2 different UCD9244 devices where each controls 4 separate power conversion devices.  The first 2 channels of U16 control the AVS supply.  These come into the VID1 and VID2 inputs but the VID2 inputs are no longer used.  At one time we considered supporting separate ARM and DSP AVS supplies but the chip was modified to only require a single AVS supply for both domains.  As you can see in the schematic, the UCD74120 devices attached to the first 2 channels have their outputs ganged together.  The configuration file for the UCD9244 shows that these two channels are controlled together by the VID1 controls.

    The K2E EVM was developed later and has a more cost effective power solution.  I recommend that you review that solution.  TI has newer power conversion devices than the TPS544C25 that can be dropped into this topology which have additional enhancements.

    Tom

  • 0 in reply to Tom Johnson 16214
    Mastermind 6850 points

    Tom,

    Hello, thank you very much for responding to my post. Can you tell me if U25 on page 41 is still necessary? Can I simply use enable U27, U8 and U23 with a microcontroller?

    Last, what is a PMBUS and do I have us use one?

    Thanks,

    Joe

  • 0 in reply to joe lindula
    TI__Mastermind 46460 points

    Joe,

    There are 2 UCD9244 devices in the design.  Each drives 4 independent output channels.  All 8 supplies are used and required in the EVM design.  Each supply voltage is required but could be produced using analog converters just as adequately as the digital converter and the associated power stages.

    Like I said, the UCD9244 is the digital supply controller.  It performs all of the start-up and shut-down sequencing as well as the calculations for the power supply control loops for 4 channels simultaneously.  Its outputs are PWM control signals which then drive the powers stages in the attached devices.  It cannot be easily replaced by a microcontroller.

    Tom

  • 0 in reply to Tom Johnson 16214
    Mastermind 6850 points

    Tom,

    Hello, thank you very much for responding to my post. Can you tell me if U25 on page 41 is still necessary? Can I simply enable U27, U8 and U23 with a microcontroller?

    Last, what is a PMBUS and do I have us use one?

    Thanks,

    Joe

  • 0 in reply to joe lindula
    TI__Mastermind 46460 points

    Joe,

    I answered the first question.  PMBUS is an I2C-like interface commonly used for power supply monitoring and control.  We considered VID control over PMBUS but this was never productized.  There is no requirement for PMBUS support to enable AVS control of the 66AK2H14 device.  However, many of the power conversion devices from TI that support remote monitoring over PMBUS.

    Tom