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TPS65100: Doubler or Trippler?

Kevin Tucker
Prodigy 40 points
Part Number: TPS65100

Our design calls for a VGH = 18V.  This would correspond to Vo3 = 18V.  The question is do I use the Doubler configuration or Trippler configuration?  In the Doubler configuration, the max Vo3 indicated on page 22 of the data sheet calls for 2xVo1 - (2xVf+2xIo(2xrdsonQ5 + rdsonQ3 +rdsonQ4)).

My Vo1 = 10V.

When using the equation with the given rdsON values, I get around 17.8V typical and 17.2V for max rdsON values.  This math would make me consider using the Trippler mode.  I cannot find where the minimum Vo3 is in Trippler mode in the data sheet, but everything on these forums say it's min is 2xVo1 = 20V.  The question then becomes, if I can't get Vo3 = 18V in Doubler mode because of the rdsOn losses, and the min for Trippler mode is too high (2xVo1 = 20V), which mode do I use?

Thanks,

Kevin

  • 0
    TI__Expert 8010 points

    Hello Kevin,

    The minimum Vo3 in tripler mode is the maximum Vo3 in doubler mode, but this is explained in the d/s. It seems that you are referring to an older revision of the datasheet. The revision from august 2016 should cover your questions. Please use this document.

    What is the output current you have and how much tolerance can you accept on VGH?

    Best Regards.

    Ilona

  • 0 in reply to Ilona
    Prodigy 40 points

    Ilona,

    Our VGH requirements are 17.8 - 18.2V @ <2mA.  Based on your post, should I be looking at the very low end of trippler mode?

    -Kevin

  • 0 in reply to Kevin Tucker
    TI__Expert 8010 points
    Hello Kevin,

    Please excuse the delayed response. Based on your requirements of VO1=10 V, IO = 2 mA and an assumption that the max. forward drop of the used diodes are in the range of 500 mV, the maximum VO3 you can get in doubler mode is 18.93 V, so I think you should be ok with the doubler mode.

    Best Regards.
    Ilona