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TPS543B20: Error Sources for Performance Analysis

vikas gupta1
Intellectual 525 points
Part Number: TPS543B20
Other Parts Discussed in Thread: TPS543C20A, TPS543C20

Hi,

We are using TPS543B20 supply in our design and wants to check the sources of error which can cause output to fluctuate, this is for the performance analysis for the supply design, Kindly share what are the possible parameters needs to add for the analysis. Also if any application note is available please share.

Thanks

Vikas Gupta

Collins Aerospace

  • 0
    TI__Intellectual 2460 points

    Hi Vikas,

    The main contributor to the output error is the internal reference tolerance on page 7. If you use external resistor divider for the output voltage, you need to account the resistor tolerance too.

    There are application notes and technical papers for this device on ti.com. You should able to find this information once you search this device on ti.com. Also, TPS543C20 and TPS543C20A are same family device with 40A.

    Kit

  • 0
    TI__Guru 56815 points

     

    There are a few potential sources for output voltage error.

    Internal Reference Accuracy is specified on page 7 of the datasheet http://www.ti.com/lit/ds/symlink/tps543b20.pdf#page=7

    There can be an additional small error introduced by the differential remote sense amplifier, also specified on page 7 of the datasheet

    If a resistor divider is used to scale the reference voltage to the output voltage, the tolerance of the resistor divider also needs to be accounted for.  The output voltage error added by the resistor divider is 2x Tolerance * (Vout/Vref - 1).  For example, using 1% resistors for a 1.2V output with a 0.6V reference, the divider can add 1% additional error to the output.

    Last, there are sense point and layout effects.  The TPS543B20 uses a differential remote-sense amplifier to minimize these, but and drop between the sensed output voltage and ground connected to the remote sense feedback points, the point of concern for the output voltage, will add additional error.  These sense points should be selected to minimize the impact of those errors.

  • 0 in reply to Peter James Miller
    Intellectual 525 points

    Hi Anthony,

    To ensure the stability do you have Average Model for the TPS543B20 IC, as we are in the analysis phase and needed to do stability analysis for the regulator we designed. 

    Else, please guide me the method to ensure the stability parameters for the regulator.

    Thanks

    Vikas G.

  • 0 in reply to vikas gupta1
    TI__Guru 56815 points

     

    I do not see an average model for the TPS543B20, but we have a transient model linked to the product folder - http://www.ti.com/product/TPS543B20/toolssoftware

    We also have an excel design tool that estimates a bode plot.  I can send you a copy of it if you would like to send me a private message with your e-mail address.