SNVA991 October   2022 LM5123-Q1

 

  1.   How to Design a Boost Converter Using LM5123
  2.   Trademarks
  3. 1Design Example
  4. 2Calculations and Component Selection
    1. 2.1  Switching Frequency
    2. 2.2  Initial Inductor Calculation
    3. 2.3  Current Sense Resistor Selection
    4. 2.4  Inductor Selection
    5. 2.5  Output Capacitor Selection
    6. 2.6  Input Capacitor Selection
    7. 2.7  Feedback Resistor Selection
    8. 2.8  UVLO Resistor Selection
    9. 2.9  Soft-Start Capacitor Selection
    10. 2.10 Control Loop Compensation
      1. 2.10.1 Crossover Frequency (fcross) Selection
      2. 2.10.2 RCOMP Selection
      3. 2.10.3 CCOMP Selection
      4. 2.10.4 CHF Selection
    11. 2.11 MOSFET selection
  5. 3Implementation Results
  6. 4Small Signal Frequency Modeling
    1. 4.1 Boost Regulator Modulator Modeling
    2. 4.2 Compensation Modeling
    3. 4.3 Open Loop Modeling
  7. 5Resources

4 Small Signal Frequency Modeling

This section provides all the equations for the control loop small signal model when the LM5123 is configured as a boost regulator in CCM operation. The simplified formulas allow for a quick evaluation of the control loop, but loose accuracy at high frequencies. The comprehensive formulas are more complex but provide better accuracy at high frequencies.