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UCC28070: how to use UCC28070 only in voltage mode and disable current mode

Part Number: UCC28070
Other Parts Discussed in Thread: UCC28063A


I wonder if ucc28070 can only work with voltage loop.

I do not want to sense the current.

So is there any way to disable the current sense pin ? ( like CSA and CSB)


  • Hello Silang Zhang,
    You will not be able to achieve power factor correction (pfc) if you disable current sensing on the UCC28070.
    All of the CCM pfc controllers need to sense current.
    You should consider using one of the TM pfc controllers such as the UCC2806x family of parts as an alternative.

  • Thank you John, 

    I have used UCC28063A  in bridgeless boost PFC beore, but there is some problems. Pls see the figures below. 

    Two auxiliary windings are used to acheve ZCD in positive and negative linecycle,respectively (see fig. 1), but the ZCD signal seems lost (or delayed) in the negative half line cycle (see Fig. 2).