SLVAFK5A December   2023  – February 2024 LM5177

 

  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
  10. 7Revision History

2.1.1 Load Balancing Requirement

Paralleling the power converters means the equal sharing of the load current, while the output voltages are the same. Figure 2-1 demonstrates the integration of two parallel LM5177 converters.

GUID-20230308-SS0I-0FWM-RTMB-PQZRGKVNFMZV-low.svg Figure 2-1 Two Parallel LM5177 Converters as Power Supply

This power supply can be modeled as a current source feeding into a common output capacitor. With the shared feedback of the output voltage the power stages are well aligned, with only slightly different of the output current balance due to device variances.

GUID-20230308-SS0I-NP5W-NQNQ-RCB2LSVLF8QP-low.svg Figure 2-2 Equivalent Model

All power stages need to be build identical with the identical inductor values and input or output capacitors so that the output variance is small enough to provide a good load balance when paralleling two or more power stages.