SNOU215 January   2025

 

  1.   1
  2.   Description
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 System Block Diagram
    2. 1.2 Kit Contents
    3. 1.3 Voltage and Current Requirements
    4. 1.4 Design Consideration
      1. 1.4.1 Boost Inductor Design
      2. 1.4.2 High Frequency Power Switch Selection
      3. 1.4.3 Input AC Voltage Sensing
      4. 1.4.4 Bulk Voltage Sensing
      5. 1.4.5 Input Current Sensing
      6. 1.4.6 Baby Boost Design
      7. 1.4.7 Relay
      8. 1.4.8 Protection
        1. 1.4.8.1 Over Voltage Protection
        2. 1.4.8.2 Over Current Protection
  7. 2Software
    1. 2.1 Quickstart guide
    2. 2.2 Download Firmware
  8. 3Power Up
    1. 3.1 Required Equipment
    2. 3.2 Considerations
    3. 3.3 Start-Up Sequence
  9. 4Implementation Results
    1. 4.1 Start-Up Waveform
    2. 4.2 THD Performance
    3. 4.3 Power Factor
    4. 4.4 Efficiency Graph
    5. 4.5 E-meter Performance
    6. 4.6 Load Transients
    7. 4.7 Input Current Waveforms
    8. 4.8 AC Drop Test
    9. 4.9 Thermal Images
  10. 5Hardware Design Files
    1. 5.1 Design Files
  11. 6Related Documentation
    1. 6.1 Supplemental Content
  12. 7External Reference

1.4.6 Baby Boost Design

To maintain holdup time and reduce bulk capacitance, a baby boost converter is added between the PFC and DC/DC as shown in the Figure 2-1. The baby boost converter is a compact boost converter that only operates during AC dropout events. During normal operation, the baby boost converter is off and bypassed by a MOSFET. When AC line dropout occurs, the Bypass FET turns off, baby boost converter turns on to ensure VBB maintains above the UVLO level for the isolated DC/DC converter. In order to minimize the magnetic dimension, the switching frequency of baby boost is set at 500KHz.