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TPSI3050: Power converter duty cycle selection in three-wire mode

Alexander Feldengut
Prodigy 220 points
Part Number: TPSI3050

Hello,

we use the switch driver in three-wire mode with a power converter duty cycle setting of 13.3 %.

Three options for selecting the 13.3 % duty cycle are given in the data sheet by using different external resistors between the PXFR pin and VSSP.

1) RPXFR = 7.32 kOhm, 1 % tolerance

2) RPXFR >= 100 kOhm

3) RPXFR < 1 kOhm

To reduce the number of components, we prefer to connect the PXFR pin directly to VSSP.

Are there advantages or disadvantages to the three options?

When using option 3), is it possible to connect a 1 kOhm resistor with 5 % tolerance (inclucing initial tolerance, temperature drift and long-term drift) or should be the resistor value < 1 kOhm

considering the tolerances?

Best regards, Alexander

  • 0
    TI__Genius 10974 points

    Hi Alexander,

    Thanks for the inquiry! If you are looking to save components, then the best option here would be to tie it directly to GND/VSSP. This will allow the pin not to float (potentially going into a different power transfer setting) and does not need any additional components.

    From a performance perspective, they are all identical in their operation and specifications, so it will not impact say any leakage numbers or anything like that.

    Hope that helps!

    Thanks!

    Bryan

  • 0 in reply to Bryan Marshall
    Prodigy 220 points

    Hi Brian,

    thanks for the fast response.

    Can you please answer the following question.

    When using option 3), is it possible to connect a 1 kOhm resistor with 5 % tolerance (inclucing initial tolerance, temperature drift and long-term drift) or should be the resistor value < 1 kOhm

    Regards, Alexander

  • +1 in reply to Alexander Feldengut
    TI__Genius 10974 points

    Hi Alexander,

    We recommend the resistor be less than 1kohms to be certain that the correct power transfer setting is selected. To be safe, tying directly to GND is the best recommendation here.

    Thanks!

    Bryan