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TINA/Spice/TPS62125: Incorrect simulation results with inverting buck-boost topology

Satish Acharya
Prodigy 230 points
Part Number: TPS62125
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

Hi,

I imported TPS62125 model from WeBench into TINA-TI. When I simulate the model with component values as described in slva514b (5V Vin and expected -5V Vout), I get Vout to go past -7.1V with load of 61 ohms.

Expected output is -5V. The output also seems to be highly dependent on load resistor.

Is the simulation model accurate ? Or, is my setup incorrect?

/cfs-file/__key/communityserver-discussions-components-files/234/TPS62125_5F00_neg5_5F00_0_5F00_1.TSC

I tried different values of Vin, R1, R2, etc but I always saw Vout much higher than expected.

I saw in another thread that inverting buck-boost topology is not supported in the SPICE models. Is this true?

Thanks,

Satish

  • 0
    TI__Mastermind 39210 points

    Satish,

    This model is not setup to support inverting topology as the internal Ground pins are shorted to Node 0. This is a limitation of the model not the device.

    We have incorporated floating GND functionality in many newer models which you can find using the link  below (when you click on the link, search for "inverting" in the search box). Please consider using one of these models for your evaluation.