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PFC + DC-DC Solution Recommendation

Victor Salomon
Expert 3660 points
Other Parts Discussed in Thread: UCC29950, LM3463

Hello team,

I am looking for a solution recommendation for the following specs:

Input Voltage: 85 - 305 VAC
Output Voltage: 56 VDC / 120W
Careabouts: low cost, space (size similar to or smaller than PMP4334), EMI Performance

It seems like the PMP4334 Reference Design is a close fit, but I was wondering if there is any recommended solutions that would be an integrated PFC + DC/DC Combo (because of of space and cost restrictions).

  • 0
    TI__Expert 3200 points

    Hi Victor,

    The PMP4334 is a 6-channel LED driver so there is no combo for this topology and number of outputs. We have combo controllers like the UCC29950 but they are going to be overkill for your 100 W power level and then if the 6 output channels is important, then you will need to add something like the LM3463. I do not have a combo to recommended based on my assumptions into your question.  Are you open on the overall architecture from what is in the PMP4334 design?

  • 0 in reply to Brian Johnson96
    TI__Expert 3660 points
    Brian,

    The 6 output channels is not important for this application, we are just looking for an output 56 VDC / 120W -- as I mentioned before I was thinking a combo solution, like the UCC29950, might be more cost effective and also save board real state.

    What would be your recommended solution given that the 6 output channel is not needed?
    What would your recommended changes on PMP4334 fit the specs (leaving the 6 Ch output out of the equation)?
  • 0 in reply to Victor Salomon
    TI__Mastermind 25590 points

    Victor,

    For your specs, you can take that design and use the PFC 50V output for your 56V output.  You may have to modify some feedback resistors (see circled in blue below) to get from 50V to 56V, but the schematic says Vout is 57.5V as it is so it might be fine.  As for the 6-channel current driver, you can remove all that circuitry.  Just use the PFC as your AC-DC converter.

    Usually we require 2 stage (PFC and DC/DC) if we need want higher power or isolation.  Since this is relatively low power and the PFC utilizes an isolating flyback topology, you've got everything you need right in this single stage.

    To get the 110W rating up to 120W, you should consider the margins that your customer requires.  If they have tight margins, you may have to change out some parts in the power train (rated current for FETs and Diodes, higher output capacitance to reduce ripple...).

    -Sam Jaffe