• State TI Thinks Resolved
  • +1 person also asked this people also asked this
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 196 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

UCC28070: We are reviewing the development of a 15kW power supply.

chulho jeong
Prodigy 90 points
Part Number: UCC28070
Other Parts Discussed in Thread: UCC28951,

Tool/software:

Hello..
I am reviewing the development of a power supply with the following specifications.
Input specifications: AC220V (AC180V~AC264V, 47Hz~63Hz)
Output specifications: 15kW (+54V/277.8A)
Height: 40mm
 The AC-DC (PFC) stage will use UCC28070, and the DC-DC stage will use UCC28951.
Question
1. Which topology is better, designing with Semi Bridgeless PFC using UCC28070 or designing with Interleave PFC?
2. Which voltage is better, designing the output voltage of the AC-DC (PFC) stage as DC400V or DC600V?
3. And is multi-phase operation possible when designing with Semi Bridgeless PFC using UCC28070?
4. Looking at the Datasheet of UCC28070, page 20, Figure 6-1, it generates an external Sync Clock. Is it possible not to use an external Sync Clock?
5. If an external Sync Clock is absolutely necessary when designing a multi-phase operation of UCC28070, please recommend a clock generation IC.
Thank you.

  • 0
    TI__Mastermind 40340 points

    Hello Chulho, 

    1.  I have no direct experience with semi-bridgeless PFC, but another engineer here does and his opinion is that the standard interleaved UCC28070 boost-PFC can be just as efficient as a semi-bridgeless PDC using the UCC28070.  If there is no significant efficiency benefit with semi-bridgeless, then the standard interleaved boost arrangement is simpler to design and implement.

    2. 400V output requires higher output current, but uses widely available semiconductors and capacitors.  600V output reduces current but requires higher rated parts, not as readily available.   Since the current is already high in both cases, it is a matter of conductor size.  At 400V, many more parts are available to choose from. 

    3.  Yes, multi-phase semi-bridgeless can be done, but it is done by making a complicated arrangement even more complicated. Multi-phase boost is also possible, but is simply adding more standard boost phases in parallel. 

    4.  Figure 6-1 on page 20 is in the UCC28951 datasheet, not the UCC28070.  Those signals are necessary for phase-shifted full-bridge converter, not for the PFC. 

    5.  External clock signals are necessary with UCC28070 for multi-phase PFC where the number of phases >2, such as 4, 6, 8 phases (must be even numbers).
    No external clock is needed for 2-phase interleaved PFC.  

    Regards,
    Ulrich