• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 3 answers
  • Subscribers 63 subscribers
  • Views 596 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.

Original question:

UCC28063: UCC28063 phase issue

UCC28063: Phase issue

Aleksandr Chaldyshkin
Prodigy 30 points
Part Number: UCC28063

I also have the phase issue. Why does the application note SNVA796–October 2017 also have non 180-degree phase shift when input voltage is 264V?

The current sensor signal of my PFC is: as it can be seen, currents are not equal.

The output voltage and input mains current are:

  • 0
    TI__Guru* 86266 points
    Hello Aleksandr,

    Application note SNVA769 describes how to manipulate the phase operation of the UCC28063. That is why they are out of phase.

    Could you double check the gate drive signal to see if they are truly not 180 degrees out of phase?

    The inductor ripple current cancelation changes with duty cycle which varies with line voltage. I believe that is all you are observing at the input.

    Please refer to the following seminar paper and review figure 3. www.ti.com/.../slup279a.pdf

    Regards,

    Mike
  • 0 in reply to Mike O'
    Prodigy 30 points

    Hello, Mike. Here are the gate signals at the top of the input mains sine current:

    and at the bottom:

    as you can see the phase shift is not 180 degrees.

    Mike, you said:"The inductor ripple current cancelation changes with duty cycle which varies with line voltage. I believe that is all you are observing at the input. "  Mike, I didn't mean cancellation, I mean an equal peak current value in the inductors. If you have a 180 degrees phase shift and equal inductance value, the peak current value must be the same.

  • 0 in reply to Aleksandr Chaldyshkin
    TI__Guru* 86266 points
    Hello Aleksandr,

    That is strange. I wonder if this has to do with the ZCDA/B signal being different. Could you study those versus the gate drives? Are the ZCDA/B turns ratios the same? Do you have any filtering on these pins and if so are they the same.

    There are few things that I know of that will cause the gate drive to go 180 degree phase shift to go out of phase.
    1. CS current limit is triggered when it comes out of it the drivers are in phase and the slowly drift out of phase.
    a. Sometime noise on the CS pin crates this and it can be removed by adding filtering capacitance to the CS pin.
    2. Coming in and out of phase management.
    a. This could be noise on the PHB.

    Besides that I have not heard of the two phases being out of phase.

    Regards,

    Mike
  • 0 in reply to Mike O'
    Prodigy 30 points

    Hello, Mike. Can you show me any application note that describes a PFC that uses UCC28063 and has oscillograms of gate signals with a 180-degree shift?

    My ZCD signals:

  • 0 in reply to Aleksandr Chaldyshkin
    TI__Guru* 86266 points
    Hello Aleksandr,

    I found the user's guide for the User's guide for the UCC28063EVM-723 www.ti.com/.../sluu512.pdf. It does not have the gate drive waveforms but has inductor ripple current in figures 11 and 12. They are 180 degrees out of phase. This EVM is orderable for you to evaluate.

    Regards,

    Mike