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  • TI Thinks Resolved

PFC device for 400W and 700W output

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Replies: 5

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Dear all

Good day !

We are going to design two kinds of ACDC power modules---- approximately 400W or 700W output.

I found the cheapest PFC device is UCC28051 which is Transition mode. Can it satisfy 400W or 700W use ?   Any problem with Inductor Ipeak ?

If it cannot be used, could you please recommend a cheap PFC device for 400W or 700W use?

Thanks

Charlie

  • 700W is beyond the power handling capability of the 8 pin UCC28051 transition mode pfc controller.

    For that power level, I suggest you use the 8 pin UCC28180 continuous conduction mode pfc controller

    Regards,

    John Griffin

  • In reply to John Griffin1:

    Hi John

    Thanks very much for your reply.

    What is the power handling capability of  transition mode PFC device?  I didn't see it in the datasheet.

    Thanks.

    Charlie

  • In reply to GU changlin:

    Hi Charlie,

    Transition mode devices are used at power levels below 100W. If you use the calculator you will find that at higher power levels the peak currents gets very high.

    This makes it difficult to find MOSFETS, diodes and capacitors that can handle the power losses and ripple involved. The power losses get a bit too high for most applications at 100W
    Also there is a point where the size of the inductor is smaller with a CCM type controller as compared with a TM type controller.  
    100W is about this point

    Regards,

    John

  • In reply to John Griffin1:

    Hi John

    Thanks a lot for your reply. It helps me a lot.
    I need both PFC device and PWM convertor/controller.PFC output is about 400W for lightning and PWM circuit, the PWM output is about 60W.
    I found UCC28180(PFC) and LM5023(PWM) combination is likely to fit our requirement, isn't it ?
    I also found TI has 2 in 1 device---UCC28521/28528.
    Would you please help to check which solution is better? or any other low-cost combination by TI devices ?

    Thanks
    Charlie
  • In reply to GU changlin:

    I have used the LM5023 in the UCC24630EVM-636 design. It is very well suited for a 60W application and it has the benefits of high efficiency quasi-resonant flyback control with low component part count.
    If you combine this part with the UCC28180 you will be utilizing two 8 pins controllers.

    The UCC28521/28 is an older part and it has pfc and PWM combined. It is a 20 pin ic and you can see that in a typical application it will require more components and pcb area. Also the pcb layout is more difficult since both controllers share a common package and it may be difficult to route all the extra traces.
    PFC/PWM "combo" type controllers are generally second generation products where the designer want to squeeze more cost out of the product.

    In your case I think the UCC28180/LM5023 combination will be the most suitable.

    Regards,

    John

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