SNVA940 November 2021 LM5157 , LM5157-Q1 , LM51571-Q1 , LM5158 , LM5158-Q1 , LM51581 , LM51581-Q1
- Trademarks
- 1LM5157 Boost Design Example
-
2Calculations and Component Selection
- 2.1 Switching Frequency
- 2.2 Inductor Calculation
- 2.3 Slope Compensation Check
- 2.4 Inductor Selection
- 2.5 Diode Selection
- 2.6 Output Capacitor Selection
- 2.7 Input Capacitor Selection
- 2.8 UVLO Resistor Selection
- 2.9 Soft-Start Capacitor Selection
- 2.10 Feedback Resistor Selection
- 2.11 Control Loop Compensation
- 2.12 Power Loss and Efficiency Estimation
- 3Implementation Results
- 4Small Signal Frequency Analysis
4.1 Boost Regulator Modulator Modeling
Table 4-1 includes equations model the plant (control-to-output) of a peak current mode boost regulator in continuous conduction mode.
Table 4-1 Power Plant Equations
| Simplified Formula | Comprehensive Formula | |
|---|---|---|
| Modulator Equations | ||
| Modulator Transfer Function |
Equation 40.
|
Equation 41.
 |
| Modulator DC Gain |
Equation 42.
 |
|
| RHP Zero |
Equation 43.
 |
|
| ESR Zero |
Equation 44.
 |
|
| Low Frequency Pole |
Equation 45.
 |
|
| Sub-Harmonic Double Pole | Not Considered |
Equation 46.
 |
| Quality Factor | Not Considered |
Equation 47.
 |
| Slope Compensation | Not Considered |
Equation 48.
 |
| Sensed Rising Inductor Slope | Not Considered |
Equation 49.
 |