TIDUBE1D January   2016  – August 2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Highlighted Products and Key Advantages
      1. 2.2.1 UCC28180 – PFC Controller
      2. 2.2.2 UCC27524 – Dual Low-Side Gate Driver
      3. 2.2.3 UCC28881 – 700-V Off-Line Converter
    3. 2.3 System Design Theory
      1. 2.3.1 Selecting Switching Frequency
      2. 2.3.2 Calculating Output Capacitance
      3. 2.3.3 Calculating PFC Choke Inductor
      4. 2.3.4 Selecting Switching Element
      5. 2.3.5 Boost Follower Control Circuit
      6. 2.3.6 Bias Power
      7. 2.3.7 On-Off Switch
      8. 2.3.8 Thermal Design
  9. 3Hardware, Testing Requirements, and Test Results
    1. 3.1 Required Hardware
      1. 3.1.1 Test Conditions
      2. 3.1.2 Recommended Equipment
      3. 3.1.3 Procedure
    2. 3.2 Test Results
      1. 3.2.1 Performance Data
        1. 3.2.1.1 Efficiency and iTHD
        2. 3.2.1.2 Standby Power and Output Voltage
      2. 3.2.2 Performance Curves
        1. 3.2.2.1 Efficiency Curve
        2. 3.2.2.2 Voltage Follower Performance
      3. 3.2.3 Functional Waveforms
        1. 3.2.3.1 Power On Sequence
        2. 3.2.3.2 Inrush Current Protection
        3. 3.2.3.3 Switching Node
        4. 3.2.3.4 Waveform Under 3.5kW, 230VAC
      4. 3.2.4 Thermal Measurements
  10. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
  11. 5Documentation Support
  12. 6Trademarks
  13. 7About the Author
  14. 8Revision History

3.2.3.1 Power On Sequence

Figure 3-4 shows the power on sequence and loading features, with switch S1 in ON status.

After power on the board, output electrolytic capacitor can be charged to build up VDCBUS through PTC RT1, so charging current can be limited, then bias supply start to work after VDCBUS is high enough to create Vbias, assuming S1 is ON status, PFC controller UCC28180 is powered on by 15V after a inrush current delay time, then PFC converter starts to work. This waveform also shows DCBUS voltage drop when PFC is loaded step by step, 1.3Arms, 5.4Arms, 7.5Arms, 9.5Arms, 10.6Arms.

There is voltage drop when load PFC.

Channel 1 is DC output voltage

Channel 2 is AC input voltage

Channel 3 is MOSFET Drain to Source Voltage.

Channel 4 is AC input current

TIDA-00779 Power On Sequences Figure 3-4 Power On Sequences