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LM5143-Q1EVM-2100: How to configure a single output with a 5V15A output from the default state.

Part Number: LM5143-Q1EVM-2100
Other Parts Discussed in Thread: LM5143

I would like to know the detailed steps to take the board from its default state to a single output with a 5V15A configuration.

Specifically:

  • The positions of switches
  • The resistors that need to be changed and their values
  • The capacitors that need to be changed and their values
  • The value of the load resistance

Thank you.

  • Hello Takashi,

    please use the LM5143 Design calculator and input your spec requirements.  the design calculator will make component value suggestions based off of your inputs.

    LM5143DESIGN-CALC Calculation tool | TI.com

    Hope this helps,

    David.

  • Takashi-san,

    See the EVM user's guide for the adjustment to 2-phase single output, including adding the output shorting bar R34, connecting the COMP pins and SS pins with the switches, removing the compensation components on COMP2, and changing the MODE pin to high. See Fig. 2 of the EVM user's guide for the schematic.

    As David mentioned, the quckstart calculator is really useful here.

    Regards,

    Tim

  • Thank you, Mr. David and Mr. Timothy,

    ①R34 → short

    ②MODE pin → VDDA

    ③COMP pins and SS pins → switch on

    ④remove short chip of R22 → short R30

    ⑤remove C51,C52,C54,R33

    Could this procedure achieve single 5V output?

    And, I have an additional question.

    Are both MOSFET switches operating at this time, or is only one of them operating?

    Thank you,

    Takashi

  • Hi Takashi-san,

    That procedure looks correct. Here is the table from the datasheet:

    In terms of the FETs, each buck leg operates at a duty cycle D, where D = Vout/Vin. More specifically, the high-side FET conducts for an interval equal to D*Ts, where Ts is the switching period, and the low-side FET conducts for (1 - D)*Ts. The second phase will be phase shifted by 180°. See the LM5143 datasheet for more detail.

    --

    Tim

  • Thank you, Mr. Timothy,

    I'm glad to hear that the steps are correct and provide reassurance.

    I will check the LM5143 datasheet for more details.

    Regards,

    Takashi