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TIDA-00779: PFC Inductor Core selection, R28 value, and conducted emissions

Simon Stringer
Prodigy 10 points
Part Number: TIDA-00779
Other Parts Discussed in Thread: UCC28180

Hi there, I'm designing a power converter that uses the TIDA-00779 reference design for the PFC front end.  The Kool Mu sendust cores originally specified in the TI reference design for inductor, L1, is part number: 0077439A7, (2x).  However, there is currently no stock of them anywhere.  I would like to specify an alternative core and I would like to use the Mag Inc design tool in order to do so as it provides the number of turns, power dissipation, and temperature rise figures which is very useful.  The Mag Inc design tool requires me to input the 'average DC current' and the 'peak-to-peak ripple current'.  Please can you let me know what these values are at full load?  Thanks!

The resistor in the snubber network for diode, D1/D3, is showing as 300k ohms in the schematic, but as a 43.2R resistor in the bill of materials.  I believe it should be a 43.2R resistor, but please could you confirm this?

The TIDA-00779 reference design is advertised as meeting surge and EFT requirements, but has the design been tested for conducted emissions, (CISPR 32), and harmonics, (IEC 61000-3-2), at all?  Even if it was tested and it failed, it would be really useful to know this at this stage in my design as I may be able to compensate for this.

Many thanks in advance!

Best regards,

Simon

  • 0
    TI__Prodigy 720 points

    Hi, Simon

    1.  TI provides a UCC28180 Design Calculator at https://www.ti.com.cn/product/cn/UCC28180#design-tools-simulation.

        You can get the current numbers with specified conditions.

    2. We recently plan to update TIDA-00779, as there are some questions from our customers, Irate=30A, 170uH MIN(at 50kHz/1V/30A), 50mohm MAX,  1.5x2mm copper wire, 54 Ts, Kool Mu core. I enclose L1 spec, but it is a Chinese version,  I will push supplier to provide an English version as soon as possible, and share it to you. 

    3. I think you are right, R28 should not be 300k so big, so pls follow value in BOM. And I will also update it in our new version schematic.

    4. As I am not the author of this reference design, and the author already left TI, I am not sure what's the test result of surge and EFT. Will see if I can find answers in next week.

    Any questions, pls let us know

    Regards

    Hely

    .Qindao Yunlu 30A-170uH inductor spec 240306.pdf

  • 0 in reply to Hely Zhang
    Prodigy 10 points

    Hi Hely, many thanks for that, much appreciated.

    I've managed to determine the inductor parameters at full load in my case, (Iav = 18A, Iripple=7.2A at 3kW load), and have selected an alternative core.  For anyone else interested, I chose the Mag Inc: 0077439A7 core , 2x cores per inductor.  This has a total power loss of 8.6W compared to the original core, (0077090A7), which is 9.3W.  Only 39 turns required due to the higher inductance factor, (Al=135nH).  

    Regarding the EMC testing, I was wondering if any conducted emissions and harmonic tests were carried out.

    Best regards,

    Simon

  • +1 in reply to Simon Stringer
    TI__Prodigy 720 points

    Hi, Simon

    You are welcome.

    I can't find EMC test result in the design guide, so I tend to believe we haven't conducted EMC test.

    And you can find harmonic test result in table 2 of the design guide.

    Regards

    Hely