TIDT369A November   2023  – April 2024

 

  1.   1
  2.   Description
  3.   Features
  4. 1Applications
  5.   Resources
  6. 2System Description
    1. 2.1 System Block Diagram
    2. 2.2 Key System Specification
    3. 2.3 Design Consideration
      1. 2.3.1 Boost Inductor Design
      2. 2.3.2 High Frequency Power Switch Selection
      3. 2.3.3 Input AC Voltage Sensing
      4. 2.3.4 Bulk Voltage Sensing
      5. 2.3.5 Input Current Sensing
      6. 2.3.6 Baby Boost Design
      7. 2.3.7 Relay
      8. 2.3.8 Protection
        1. 2.3.8.1 Over Voltage Protection
        2. 2.3.8.2 Over Current Protection
  7. 3Power Up
    1. 3.1 Required Equipment
    2. 3.2 Considerations
    3. 3.3 Start-Up Sequence
  8. 4Testing Results
    1. 4.1 Start-Up Waveform
    2. 4.2 THD Performance
    3. 4.3 Power Factor
    4. 4.4 Efficiency
      1. 4.4.1 Efficiency Graph
      2. 4.4.2 Efficiency Data
    5. 4.5 E-meter Performance
      1. 4.5.1 E-meter Graphs
      2. 4.5.2 E-meter Data
    6. 4.6 Load Transients
    7. 4.7 Input Current Waveforms
    8. 4.8 AC Drop Test
    9. 4.9 Thermal Images
  9. 5External Reference

2.3.2 High Frequency Power Switch Selection

As wide-bandgap devices are the necessary high frequency power switches for a CCM totem-pole bridgeless PFC Boost rectifier, TI “GaN CCM Totem Pole PFC Power Loss Calculation Excel Sheet” is used to estimate the loss on the power switches and select which GaN device is applicable. A screen shot of the calculation results is shown in Figure 2-3. 30mΩ GaN devices (LMG3522R030 or LMG3422R030) are eventually selected for this design.

GUID-6B1CA081-B5A5-49D9-82C4-C44064466742-low.png Figure 2-3 GaN FET Loss Calculation for CCM Totem Pole Bridgeless PFC