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PMP4259 (UCC28070) Inductor question


I have checked the Schematic, PCB and BOM of the PMP4259 as I am desigining a >3kW PFC. However, I cannot understand how the Boost inductors have been used.

From the BOM I have found that the SRW42EC is actually a transformer (Datasheet atached) and I have seen in the PCB that it should have 4 pins on one side and 6 on the other one. But I can not find any component matching any of these specs.

Also, in the Schematic is commented as 200uH but appears as 250uH in the BOM.

Could somebody explain how this components have been selected? Is it actually a transformer?

Thanks in advance.

  • The part is an inductor. Its inductance is 250uH at 0A and 200uH with 17A. The drawing you attached is not the drawing for L1 or L2. It is a drawing for the bobbin and core. A drawing for the inductor would be a specific drawing for that part showing electrcial specifications for inuctance and mechanical data showing the pins used in the bobbin. In this case the pins used are 3,4 7 and 8. Your confusion was caused because an incorrect part number was used in the BOM. The BOM used a generic bobbin/transformer number and a unique part number was not issued for the inductor. Sorry about the confusion.

    John Griffin

  • Hello John,

    Thanks for the fast answer.

    Is it possible to have a part number for that inductor?

    Thanks again.

  • Hi Borja,

    Unfortunately a proper part number was never assigned to inductor. But you have all of the necessary information to request an inductor from a magnetics manufacturer. All they require is the footprint, and the inductance value at no load and at fulll load.