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TPS546A24A: TPS546A/B/D24A possible output voltage

Genius 11795 points
Part Number: TPS546A24A

Hello Team,

there is some confusion regarding the possible Vout for TPS546A/B/D24A.

All their datasheets specify on page 1:

and on page 12:

 Question: Is it possible to set Vout to 6V?

Thanks and Best Regards,

Hans

  • Hi Hans,

    Peter will look into this and feedback to you soon.

    Thanks,

    Lishuang

  • Hans,

    The PMBus command is digitally programmable over a range from 0.25V to 6.0V, but the VOSNS pin is only rated for 5.5V so we do not recommend programming the part above 5.5V.

  • Hi Peter,

    thanks for fast reply! If I add a R-divider (e.g. divide by 2) between Vout and VOSNS I don't violate the maximum rating. I just read half of Vout when using READ_VOUT, correct?

    In that case I can set Vout to 6V, correct?

    Or are there other reasons which prevent this use case, please?

    Thanks and Best Regards,

    Hans

  • Hans,

    Yes, it would be possible to set the output voltage upto 6V using an external divider, though I would not recommend a 2:1 divider.

    You will need to pay careful attention to the input impedance of the VOSNS to GOSNS pins, as that will affect the divider accuracy.

    You can set VOUT_SCALE_LOOP to a value less than 0.125 so the part can correct for the external divider along with its internal divider.  That will allow both VOUT_COMMAND and READ_VOUT to work correctly.

    For example, if you add an external divider 0.8x divider (1R over 4R) and programming VOUT_SCALE_LOOP equal to 0.100, the internal divider will be set to 8:1 (VOUT_SCALE_LOOP < 0.125) but the reference voltage will be set to VOUT_COMMAND x 0.100 and READ_VOUT will report 10x the voltage measured at the 8:1 internal sense voltage, so the part will compensate for the total 10:1 divider.

    Using this will allow output voltages up to 6.0V, but output voltages above 6V could saturate the ramp in the PWM modulator and should not be used.