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

2.10 Control Loop Compensation

Type II compensation network is adequate to stabilize the control loop for a peak current mode architecture. A generic technique for selecting the crossover frequency and placement of the error amplifier the pole and zero resulting in a stable system in CCM is presented. The detailed models of the control loop are presented in Section 4. The following section guides the reader through the process of selecting the control loop compensation components; RCOMP, CCOMP and CHF as shown in Figure 2-5. Figure 2-6 shows the type II response of the compensation network. GMea and RCOMP sets the mid band gain (gMID) of the compensation network. The zero frequency fZea is set by the combination RCOMP and CCOMP. The pole is set by the combination of RCOMP and CHF.

Figure 2-5 Control loop compensation network
Figure 2-6 Type 2 Compensation