SNVAA87 august   2023 LMR38020

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Micro Inverter System
    2. 1.2 Typical Power Tree and Design Requirements
  5. 2Conventional Flyback Design Challenges
    1. 2.1 SSR Design Challenges
    2. 2.2 PSR Design Challenges
  6. 3New Fly-Buck Design
    1. 3.1 LMR38020 Overview
    2. 3.2 Comparison with Conventional Flyback
    3. 3.3 Design Considerations
    4. 3.4 LMR38020 Fly-Buck Design Example
  7. 4Bench Test and Result
    1. 4.1 Start Up
    2. 4.2 Typical Switching Waveforms Under Steady State
    3. 4.3 Efficiency
    4. 4.4 Load Regulation
    5. 4.5 Short Circuit
    6. 4.6 Thermal Performance
  8. 5Summary
  9. 6References

4 Bench Test and Result

Figure 4-1 shows the LMR38020 Fly-Buck™ application schematic for micro inverter and Figure 4-2 shows the demo board top view.

GUID-20230807-SS0I-CMB6-TLMS-12SM6QPXQTKT-low.svgFigure 4-1 LMR38020 Fly-Buck Application Schematic for Micro Inverter
GUID-20230807-SS0I-FH0V-1LKQ-RC4MBSKBZTNJ-low.png Figure 4-2 LMR38020 Fly-Buck Demo board for Micro Inverter

The demo board is tested almost over full-range line and load variation. In short, the efficiency can be up to 96% at VIN=24V and full load, as shown in Figure 4-9 and Figure 4-10. The regulation tolerance on the primary Vout is approximately 1% and the secondary Vout is <10% as shown in Figure 4-11 and Figure 4-12.