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Original question:

WEBENCH® Tools/UCC28070: multiple phase interleave PFC

WEBENCH® Tools: Multi-Interleaved PFC Solution (ala UCC28070)

Jeff Melvin
Prodigy 170 points
Other Parts Discussed in Thread: UCC28070, UCC2817, UC3854, UCC2818, UCD3138

Tool/software: WEBENCH® Design Tools

In a previous post Peter Meaney stated "TI has no plans to release a three phase interleaved solution."  (e2e.ti.com/support/power-management/f/196/t/718550)
    I believe this response does address the question posed (a triple-interleaved PFC, not a three-phase mains input PFC).

Another post is questioning using two UCC28070 controllers with a phase-shifted clock to obtain a quad-interleaved PFC.  (e2e.ti.com/support/power-management/f/196/t/765400)

Can you recommend an existing controller that could be ganged together (in clock and control) to obtain a triple-interleaved PFC result?
    I don't want to list a competitor, but there is an option from another supplier.  I would like to compare this with a TI (even if it's a multi-chip) solution.

While I'm interested in a triple-interleaved solution, perhaps the requested solution would be suitable for a generic multi-interleaved approach?
    This would promote a "Lego" block approach for us, where individual interleave blocks could be ganged to obtain higher powers.

  • 0
    TI__Intellectual 1615 points
    Hi, Dox,
    I assume you are planning to run the PFC in the continuous conduction mode (CCM). If that is the case, there are many options. However, if you are planning to operate it in transition mode (TM), or sometimes called critical conduction mode or boundary mode, it is going to much more complicated.
    For the CCM operation, you can use any of our CCM PFC controller with the sync capability, such as UC3854, UCC2817, UCC2818, etc.
    First of all, you need to have the clock signal to sync three of these controllers to be 120 degree out of phase.
    Second, you need share their voltage loop using a single device's voltage loop so that every phase has the same current reference.
    Third, you'll have to use two current transformers in each channel, one in series with the MOSFET and one in series with the diode, to reconstruct the current. Because the current sense resistor won't work in the interleaved structure. UCC28070 has the scheme to save some current transformers.
    After these steps, you can glue the whole thing into a whole controller that controls the three channel interleaved PFC.
    Given the complexity you have, It might be cheaper to run 4 phase interleave since it is already a designed solution and it is much easier than glue all the necessary circuit together. It only uses 4 current transformers instead of 6, two controllers instead of 3. And you can further spread the heat out and improve the reliability.
    Of course, you can always use the digital controllers, such as UCD3138 or C2000 to implement it.
    I hope this gives you some idea of implement this.
    Bing