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TPS22810: QOD resister power rating

Toshihiro Watanabe
Genius 10235 points
Part Number: TPS22810

Hello,

When QOD speed controls by external resister, How to determine the resister power rating?

It will be short duration but peak power may be big. It would be helpful if there is a guidance how to design it/

Best regards,

Toshihiro Watanabe

  • 0
    TI__Genius 10855 points

    Hi Watanabe-san,

    Thanks for reaching out on E2E!

    The calculation depends on the value chosen for the external QOD. After adding the external QOD and internal QOD together, you can find the power dissipating through the resistor by doing P  = I^2 *R.

    As an example, if the output voltage is 12V, there is a 300Ω external QOD resistance, and the DBV package is being used, then the total current into the QOD pin is:

    QOD Current = VOUT / (External QOD + Internal QOD)

    QOD Current = 12V / (300Ω + 265Ω)

    QOD Current = 21.2mA

    Then, the power going through the resistor is calculated as:

    Power = IQOD^2 * External QOD

    Power = 21.2mA ^2 * 300

    Thanks,

    Arthur Huang