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Original question:

TPS61197: Question about output capability

TPS61197: TPS61197

Julian Hiorns
Prodigy 150 points
Part Number: TPS61197

I'm trying to calculate the OVP resistor values using the data sheet revised June 2017. The given formula is R3 (top resistor) = ((Vout_ovp - 1) / 3.04) x R4 (bottom resistor). The problem is that I can't make the values used in the example schematics match this formula, or in the evaluation board schematic, for that matter. For example, the example resistor values of 1M and 20K respectively give an OVP value of 149V! Does anyone know of a revision to this formula or why the values don't correspond?

  • 0
    TI__Mastermind 22745 points
    Hi Julian,
    In the evaluation board, R4=10k,R3=191k, Vout_ovp is calculated about 60V. That's right. Is there any question? There is no vlaue that don't correspond? Can you check again?
    Regards
    Sean
  • 0 in reply to Sean Zhou
    Prodigy 150 points

    Hi Sean,

    Thanks for your reply. You're right - I made a mistake in looking at the schematic. My confusion arose initially becaause page 1 of the data sheet shows values for R3 and R4 of 1M and 20K. This error (assuming the OVP is not meant to be 155.04V!) is repeated throughout the data sheet and I couldn't reconcile this with the formula.