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Webench/TPS54360: Fantastic efficiencies on Webench, more than datasheet

Michael Markowitz1
Prodigy 50 points
Part Number: TPS54360

Tool/software: Webench

Hi,

My design parameters are vin 18-36V, 12V / 3A output and 150kHz. I'm getting efficiancies of ~95-98%.

In the datasheet there are no graphs for 12V so I designed in the Webench for one of the designs that have a graph in the datasheet and I still got efficiancies a few percent higher than the datasheet.

Are the efficiancies in Webench realistic?

Michael

  • 0
    TI__Mastermind 26780 points

    Hi Michael,

    Within WEBENCH, we try to estimate efficiency within 3% accuracy in the higher current region and about 4-5% accuracy in the lower current region using a physics based model for losses. We model efficiency for the EVM design in various cases and try to match the efficiency across corners.  

    I created the datasheet or EVM user's guide(www.ti.com/.../slvu769b.pdf)  design in WEBENCH by matching the Vin, Vout, Iout, switching frequency, and major lossy components like L1 and D1. I see the lower current region error is as high as about 5% in some higher Vin cases like I pointed out above (I shall run this by my colleague to see if this error can be reduced further). However, the accuracy of efficiency gets much better in the higher current region (within 2-3%). I also created the 12V design with 150kHz Fsw and see ~98% efficiency at lower currents like 0.5A or so. The reason the efficiency is higher in lower current regions is due to low Fsw leading to low switching losses.

    I would recommend using WEBENCH efficiency as a good starting point for your design and then building evaluation board to measure the efficiency in order to ensure that your requirements are met. 

    Please let me know if you have any more questions. 

    Regards,

    Amod