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TPS546E25:Review of TPS546E25 Schematic

INGI MIK
Prodigy 20 points
Part Number: TPS546E25
Other Parts Discussed in Thread: TPS543C20A

Tool/software:

Hello,

I am designing a converter using the TPS546E25 with the following specifications:

  • Input: 12 V (range: 11.4 V to 12.6 V)

  • Output: 4.0 V or 4.5 V

  • Load current: 50 A

    If you have a TPS546E25 calculation document, please share it.3404.TPS546E25.pdf

  • No PMBus used — I intend to apply component values from the TPS543C20A design (since a TPS546E25-specific calculator/document is unavailable).

I would appreciate your help reviewing the design for any potential issues.

In addition, I have two specific questions:

  1. CNTL (ENABLE) pin:
    The datasheet states that the logic HIGH threshold is typically 1.2 V. If I apply 1.8 V to CNTL, will the device recognize it as HIGH and operate normally?

  2. PMB_ADDR pin:
    Since I am not using PMBus, can I leave the PMB_ADDR pin floating, or should I tie it to a defined logic level?

Thank you in advance for your support.

  • 0
    TI__Genius 11155 points

    Hello,

    Please allow some time to respond as there is heavy customer support at the moment.

    Thank you,

    Calan

  • 0 in reply to Calan Elaya
    Prodigy 20 points

    The schematic I previously shared had some incorrect connections, so I have made corrections.
    Please review the updated schematic attached here.7536.TPS546E25.pdf

  • +1 in reply to INGI MIK
    TI__Mastermind 23695 points

    Hello

    Here is an example schematic when using an external divider and a made comments on the schematic.


    7536.TPS546E25_comments.pdf

    Also, webench is available on the bottom of product folder for creating designs. 

    Power Designer

  • 0 in reply to David_Daniels
    Prodigy 20 points

    Hello,

    Thank you for your help in identifying the issues with my circuit design. Your feedback was very helpful.

    I have made the requested modifications: the MSEL1 resistor is now 26.7kΩ, and the VSEL/FB connection has been updated according to the attached diagram.
    TPS546E25_250904.pdf

    I am still facing some issues, as Webench Designer indicates that the TPS546E25 product is not available for design. In light of this, I have a few questions:

    1. Could you please confirm if the TPS546E25_Calculator.xlsx document can be shared?

    2. I need some clarification on the CNTL (Enable) Pin voltage. The datasheet specifies that the absolute maximum rating is 5.5V and that a "high" signal is recognized at 1.2V or above. However, another section states that the "Enable Max high" is 1.3V, which is confusing. Can I safely input 1.8V to the CNTL pin?

    Thank you for your time and assistance.

  • 0 in reply to INGI MIK
    TI__Mastermind 23695 points

    The EC table has rising CNTL pin voltage at 1.2V typical and maximum of 1.3V.   

    Generally speaking at room temp on the bench, the threshold you will witness is 1.2V.   

    But when including process, temperature and voltage and test limit variation in the threshold, the maximum is 1.3V.TPS546E25_250904_comments.pdf

    accept my e2e friend request and I can share a calc tool.

    The reason the webench is not working for you, is the power dissipation is very high for 4.5V and 50A.   You should consider 2 phase configuration. 

  • 0 in reply to David_Daniels
    Prodigy 20 points

    Hello,
    I’ve sent you a friend request. Could you please share the TPS546E25_Calculator.xlsx file?

    I’ve also updated the comments you provided.

    TPS546E25_SCH_250905.pdf

    Thank you.

  • 0 in reply to INGI MIK
    TI__Mastermind 23695 points

    The tool was sent via e2e mail. 

    Not sure if the SN74AVC2T45DCUR is needed. 

    The CNTL pin will recognize 1.2V or greater as a high when the voltage rising from 0V. 

    Worse case is 1.3V or greater is recognized as high.   To guarantee a "high" 1.3V or greater should be applied. 

    Do not place 5.5V or greater to CNTL, this will damage device.

    Regards,

    David