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UCC28070: Resistive Sensing with UCC28070 questions and challanges

Part Number: UCC28070

Tool/software:

Hello all,

We are designing a 1.5kW PFC using UCC28070 with universal input, facing all sorts of challenges in selecting a current transducer with transformers ( like their limited avialibitiy , sizing, prices, ...) we came through a solution TIDA-01390A(001) which uses shunt resistors and opamps (much-preferred way) for current sensing, however we realized there are many challenges for this, in any case in the schematics of TIDA-01390A(001) what we don't understand is the presence of those series inductances/trasnformers of L1,L2 and L3,L4 per each leg, can we know what are those?

Thanks

MM

  • Hello MM, 

    L1 and L2 are collectively the boost inductor of this PFC converter.  They are not transformers, simply two separate but identical inductors connected in series. 
    L3 and L4 are the same thing. 

    I suspect that the designer of that TIDA design used two smaller commercially-available inductors rather than design a single custom-value inductor for this application. 
    The main purpose of this TIDA design is to showcase the use of source-based sense resistors instead of drain-based current transformers, so the choice of inductors was a secondary consideration.   

    Each one's actual part number is CTX16-18405-R (140uH) from Eaton Electronics. 

    Regards,
    Ulrich