SLVAFW9 August   2024 LM51772

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Parallel or Multiphase Power Stages
    1. 2.1 Paralleling Power Stages
      1. 2.1.1 Load Balancing Requirement
    2. 2.2 Clock Generation
    3. 2.3 Interconnection of the Power Stages
  6. 3Application Implementation
    1. 3.1 Soft-start Capacitor
    2. 3.2 Compensation
    3. 3.3 Input and Output Capacitor
    4. 3.4 Usage of the Average Current Sensor
  7. 4Test Results
    1. 4.1 Load Current Balancing
    2. 4.2 Inductor Current
    3. 4.3 Thermal Images
      1. 4.3.1 Dual Phase Operation at Variable Load
      2. 4.3.2 Comparison Between Single Phase and Dual Phase Operation
  8. 5Summary
  9. 6References

Abstract

This application note explores how to implement the parallel operation of buck-boost converters using the LM51772 Buck-Boost Controller IC. The LM51772 is designed to handle a wide range of input voltages and can operate in buck, boost, or buck-boost modes, making the device a flexible choice for various power supply designs. When higher output currents or system redundancy are needed, using multiple LM51772 controllers in parallel can be an effective design. This document guides users through the practical steps of setting up parallel operation with the LM51772, focusing on key factors like verify the controllers share current evenly, maintain loop stability, and manage heat dissipation. This application note also addresses the challenges of parallel operation, particularly the potential for current-sharing errors, and offers practical advice on reducing these errors. Real-world design examples, simulation results, and experimental data are presented to demonstrate the effectiveness of the proposed configurations.

By following the guidelines in this application note, designers can optimize power delivery and verify reliable operation in demanding power conversion applications.