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UCC28070-Q1: Interleaved PFC Boost Converter Current sense design

Part Number: UCC28070-Q1
Other Parts Discussed in Thread: UCC28070

Hi,

I was designing a Interleaved PFC Boost Converter with a power rating of 3.5kW. Is it possible to modify the current cense circuit by replacing the C.T with a current sense resistor as the C.T is making the circuit too bulky and the PCB design tough.

  • Hi Sithara,

    It is possible to replace the CT with a sense resistor between source and ground of the MOSFET, however, you have to take into account the IxR power loss and its impact your system efficiency.  You may consider using a smaller resistor with a high-speed op-amp to gain up the sense resistor signal to reduce this effect. Keep in mind the input voltage range of the CS amps and try to utilize as much of it as possible to reduce the SNR of the CS signal.  Attached is an example from a 300W design: 6011.TIDA-0130A(001)_Sch.PDF

    Make sure you are using the UCC28070 Calculator Tool  https://www.ti.com/lit/zip/sluc114 as the Webench designer may not be as accurate with the magnetics selection.

    Regards,

    Ray

  • Hi Ray, 

    Thanks a lot for the prompt  and fast reply. Will try to modify my design as you suggested.

    Regards,

    SitharaM