SNVAA82
august 2023
LMR38020
1
Abstract
Trademarks
1
Introduction
2
Fly-Buck Converter
3
Fly-Buck Basic Operation
3.1
Basic Intervals of Steady State Operation
3.2
Impact Of Leakage Inductor On Fly-Buck Operation
4
Design A Fly-Buck Converter with LMR38020
4.1
IC Select
4.2
Switching Frequency Set
4.3
Transformer Design
4.3.1
Turns Ratio
4.3.2
Magnetic Inductance
4.3.3
Check Ipk
4.4
Output Capacitor Selection
4.4.1
Primary Output Capacitor
4.4.2
Secondary Output Capacitor
4.5
Secondary Output Diode
4.6
Preload Resistor
5
Bench Test Results
5.1
Typical Switching Waveforms Under Steady State
5.2
Start Up
5.3
Efficiency
5.4
Load Regulation
5.5
Short Circuit
5.6
Thermal Performance
6
Design Considerations
7
Summary
8
References
Application Note
Designing an Isolated Buck Converter using the LMR38020