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TPS53689T: [Mitac E7142] Nonlinear function OSR & USR on GUI

Vincent Hsieh
Intellectual 1980 points
Part Number: TPS53689T
Other Parts Discussed in Thread: CSD95510

Tool/software:

Hi teams,

Currently I'm testing the TPS53689T + CSD95510 solution for customer and try to optimize the config code to let all transient margin >10mV.

And I using Nonlinear function OSR & USR to reduce over and undershoot voltage, also see the TPS53689T datasheet section 7.3.4.7 to see the OSR and USR function.

But customer tell me they don't want us using OSR and USR function because they have used other competitor controller whit similar function and cause overtemperature issue.

My questions are:

  • Will OSR and USR cause device temperature increase?
  • Datasheet only explan about Body Braking, how other OSR function works? 
    • Pulse Truncation Only
    • Body Braking + Pulse truncation
    • Body Braking only
    • Pulse Truncation with all phases at tON.
  • How USR function works?
  • Do we have related document and test report explain more about this?

Thanks,

Vincent

  • +1
    TI__Prodigy 410 points

    Hi Vincent,

    The over temperature issue what client mentioned is OSR function with Body Braking, which means the PWM will be tri-state and the continuous inductor current will go through body diode of low side MOS after trigger OSR function. That will be the temperature rising because of the large free wheeling current from inductor x Vdiode.

    We do recommend that enable OSR function without Body Braking.

    For both OSR and USR functions, please refer to the 7.3.4.7 Nonlinear: Undershoot Reduction (USR), Overshoot Reduction (OSR) and Dynamic Integration in datasheet.

    Best regards,

    Jack Su