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TPS61240 increasing output voltage by 10% with an external FB resistor

Other Parts Discussed in Thread: TPS61099, TPS61252

Hi,

I am considering using the TPS6124x as a booster for supplying an audio amplifier.

The power source is a typical Li-ion battery, but I require a 5,5V output rather than 5V.

Looking at the datasheet it looks lke adding an external resistor in series with the FB pin, from the Ouput Voltage pin would allow one to slightly tune up the output voltage since the maximum voltage on the output pin is 7V anyway.

The internal feedback network resistor values for R1 & R2 are not mentioned but I assume they would be in the 100s of KOhm.

Can Ti supply these values please, including the internal band-reference voltage ?? Would there be any potential issues with this increase in voltage to 5,5V with regards to correct booster operation ? Just wondering ....

Regards,

Michael

  • The internal feedback resistor is R1=724k, R2=228K, and the reference voltage is VREF=1.2V. but the variation of the resistor is +-14%, this may cause 5.3V~5.7V output voltage variation if VOUT is set to 5.5V.

    what about TPS61099 for this application?
  • Hi Jasper,

    Electrically it would be a great part, but there is only one BGA style package available, and this may pose a problem for standards that we will need to follow... Essentially we have to limit conductor-conductor sepparations on any component or track on our board to 0,2mm. It would appear the ball array pitch is 0,4mm and the maximum ball diameter is 0,3mm ... we would deffinitely be on a limit in a worst case and I'm trying to avoid ultra-compact BGAs especially on the power management.

    I was thinking more of a WSON or similar package (but not smaller) to avoid any potential certification issues in the future ... Is there a TPS61099 or similar in a WSON package ?

    Regards, Mike

  • i thought you want BGA...
    you can have a look at TPS61252.