SNVAA82 august   2023 LMR38020

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Fly-Buck Converter
  6. 3Fly-Buck Basic Operation
    1. 3.1 Basic Intervals of Steady State Operation
    2. 3.2 Impact Of Leakage Inductor On Fly-Buck Operation
  7. 4Design A Fly-Buck Converter with LMR38020
    1. 4.1 IC Select
    2. 4.2 Switching Frequency Set
    3. 4.3 Transformer Design
      1. 4.3.1 Turns Ratio
      2. 4.3.2 Magnetic Inductance
      3. 4.3.3 Check Ipk
    4. 4.4 Output Capacitor Selection
      1. 4.4.1 Primary Output Capacitor
      2. 4.4.2 Secondary Output Capacitor
    5. 4.5 Secondary Output Diode
    6. 4.6 Preload Resistor
  8. 5Bench Test Results
    1. 5.1 Typical Switching Waveforms Under Steady State
    2. 5.2 Start Up
    3. 5.3 Efficiency
    4. 5.4 Load Regulation
    5. 5.5 Short Circuit
    6. 5.6 Thermal Performance
  9. 6Design Considerations
  10. 7Summary
  11. 8References

5.5 Short Circuit

The LMR38020 enters hiccup protection mode when the primary side output is shorted, as shown in Figure 5-13. Once the short condition is removed, the converter is automatically recovered..

GUID-20230802-SS0I-31P6-02QH-JZ5DH1G6MWZR-low.pngFigure 5-13 Short Circuit On Primary Output
GUID-20230802-SS0I-DJLC-K7FP-DFLQKJMPXXKZ-low.pngFigure 5-14 Short Circuit On Secondary Output