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TPS62865: Ways to set the output voltage

Dice-K
Mastermind 6330 points
Part Number: TPS62865

Hi support team,

I think there are two ways to set the output voltage.
 - Resistance voltage divider by R1 and R2.
 - Connect R4 to VSET terminal.

Please let me know advantages and disadvantages of each ways and the recommended way.

Regards,
Dice-K

  • 0
    TI__Genius 14856 points

    Hello Dice/K,

    You are right, there are two ways to set the output voltage.

    Typical schematic are shown on first page of the datasheet.

    If you are using the resistive bridge R1 & R2, you have more room to set the exact VOUT value you want by controlling the R1/R2 ratio. There may be the specifc VOUT value in Table 8-2 you require for your system.

    If you are using R4 to set the output volateg with VSET, you will be using one resistor less which saves you space and cost.

    Let me know if you have more questions.

    Thanks,

    Dorian

  • 0 in reply to Dorian Brillet de Cande
    Mastermind 6330 points

    Hi Dorian,
    Thank you for your reply.

    From your answer I feel like using R4 and VSET is a better way.
    Are there any disadvantages to using R4 and VSET?
    Is the output accuracy higher for only one R4 because there are fewer external parts?

    Best regards,
    Dice-K

  • +1 in reply to Dice-K
    TI__Genius 14856 points

    Hello Dice-K,

    You can read the following White paper which discusses also aboput this.

    The output accuracy with the R4 method doesn´t depend on the accuracy of the R1/R2 resistors that you would use.

    So to some extent yes, this provide a tighter output accuracy.


    Thanks,

    Dorian

  • 0 in reply to Dorian Brillet de Cande
    TI__Genius 14856 points

    Hello Dice-K,

    I didn't hear back from you.

    Do you have any follow up questions ?

    Let me know!

    Thanks,

    Dorian

  • 0 in reply to Dorian Brillet de Cande
    Mastermind 6330 points

    Hi Dorian,
    Thank you for your support.

    Sorry for replying late.

    From your answer and the white paper, I have understood the Important points of advantages and disadvantages of R2D as follows.

    Advantages
    - Elimination of FB current.
    - Smaller size and lower cost.
    - Tighter output voltage accuracy.

    Disadvantages
    - Only the output voltage shown in Table 8-2 is generated. For example, 3.0V cannot be generated.
    - Longer startup time. However, since it is within 1 ms, it does not generally matter.

    Overall, I think R2D is better.

    Please let me know if there is something wrong with my understanding.

    Best regards,
    Dice-K

  • 0 in reply to Dice-K
    TI__Genius 14856 points

    Hello Dice-K,

    Your understanding is good.

    Let me know if you have more questions.

    Thanks a lot!

    Regards,
    Dorian