SLUAAD0 September   2021 UCC28064A

 

  1.   Trademarks
  2. 1Introduction
  3. 2Normal Theory of Multi Phases Control UCC28070 and UCC28064A Operation
  4. 3Achieving Adjustable Phase Control Operation with UCC28064A
  5. 4Achieving Multi Phases Control Operation
    1. 4.1 Disable Feedback of Secondary (Connecting VSENSE and VREF Directly)
    2. 4.2 Disable Feedback of Secondary (Connecting VSENSE and VREF with Diode)
    3. 4.3 External 4 Multi-phase Mode Control Circuit of UCC28064A
    4. 4.4 Detail Operating for External Paralleling Two-Power Stages Control Circuit of UCC28064A
    5. 4.5 Test result for External Paralleling two power stages control circuit of UCC28064A
  6. 5Summary
  7. 6References

4.4 Detail Operating for External Paralleling Two-Power Stages Control Circuit of UCC28064A

There are 2 TM PFC control IC’s, a primary and secondary. Each one has internal comparators and reference voltages which are independent of the other. When COMP is connected between the two pins, both 20-mV COMP-Discharge comparators must be satisfied before each load on COMP will be released.

There are several important highlights to note from Figure 4-3. By connecting VSENSE to VREF with a diode, the feedback of the secondary controller is disabled. Also, because both the primary and secondary controllers share a common COMP pin, they will have the same constant on time. The two UCC28064s will have their own zero cross detection (ZCD) and other protections such as 1st OVP, 2nd OVP, OCP and OTP can be set individually.