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TPS50601A-SP: Worst-case analysis of DC output regulation

Gregory Duperon
Expert 7470 points
Part Number: TPS50601A-SP

I have a customer attempting to do a worst-case analysis regarding regulation.  Customer requires +/- 3% regulation.

This device has a 1.5% accurate reference, which impacts voltage accuracy.  Resistive feedback network tolerances will also impact accuracy.

Are there any additional internal device tolerances that could impact accuracy the customer should include in the worst-case analysis?

In addition, customer plans to use a parallel configuration in some cases?  Will accuracy be worse in a paralleling scheme?

Thanks.

  • 0
    TI__Expert 4420 points
    Hi Gregory, for DC regulation you are correct. The VREF accuracy and the tolerance of the feedback resistors will be the dominant factor. Just to clarify, the +/-3% that the customer requires is only for DC? Typically the regulation requirements try to include transients, DC effects and drift (TID and aging). The +/-1.5% VREF accuracy in the TPS50601A-SP includes load, line, temperature, TID and aging effects so you are good there. However, if the +/-3% includes AC effects as I suspect, you will need to take other factors into consideration such as output capacitance and loop response.

    Thanks,

    JV
  • 0 in reply to Javier Valle
    Intellectual 260 points
    Hello Javier,

    I am the customer Greg mentioned. Thanks for the information, very helpful. I also intend to consider how AC effects such as output ripple will impact my 3% requirement, but wanted to start with DC accuracy. One question you did not address: Will Vout DC accuracy (based on internal VREF and external feedback resistors) be the same in the parallel device case as in the single device case? I would expect this to be true, since the master is controlling Vout in the parallel case using the same control loop, but let me know what you think.

    Thanks, Ted
  • 0 in reply to Ted Wolfe
    TI__Expert 4420 points
    Hi Ted, correct, as a worst case, the VREF accuracy will be the same if in parallel. How much current do you need for your application?

    Thanks,

    JV
  • 0 in reply to Javier Valle
    Intellectual 260 points
    Thanks Javier,

    We have multiple voltage rails with differing current requirements. For the rails we plan to power with parallel 50601A's, the current requirements range from 5.4A to 9.6A.

    -Ted