SLVAFK5A December   2023  – February 2024 LM5177 , LM51770

 

  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

4.2 Inductor Current

Figure 4-3 through Figure 4-10 shows the inductor current for different converter topologies at 2 A and 10 A load currents. The inductor current shown in all figures verifies the accurate load sharing and phase shift of 180 degrees among two parallel phases. A small error in the inductor peak current can be seen through the scope plots. This error is caused by the slight variation in the selected inductor values. The measured inductor value for phase 1 and phase 2 is 3.631 µH and 3.654 µH, respectively. Therefore, it is recommended to use the same inductor value with similar tolerance for the parallel operation. Also, in all input voltage conditions, no prominent ripple is seen in the output voltage of the parallel operation. Thus, it confirms the quality of output voltage regulation of LM5177 converters in a parallel fashion.

GUID-20230502-SS0I-LRMW-FRPX-XXJLQN0GVS4T-low.pngFigure 4-3 Inductor Current in Boost Region (VIN=8 V and 2 A Load)
GUID-20230502-SS0I-JFTK-PZ1T-7ZJXJQP415R8-low.pngFigure 4-5 Inductor Current in Boost Region (VIN=10 V and 2 A Load)
GUID-20230502-SS0I-WTP7-JKRJ-KVRLBZQ7XBV9-low.pngFigure 4-7 Inductor Current in Buck-Boost Region (VIN=16 V and 2 A Load)
GUID-20230502-SS0I-W2P0-X0S8-7FLMM6KMQM1W-low.pngFigure 4-9 Inductor Current in Buck Region (VIN=30 V and 2 A Load)
GUID-20230502-SS0I-ZKTW-BCV6-26VXDH983WGR-low.pngFigure 4-4 Inductor Current in Boost Region (VIN=8 V and 10 A Load)
GUID-20230502-SS0I-1M8K-G1PR-CSW9TMJWR5JP-low.pngFigure 4-6 Inductor Current in Boost Region (VIN=10 V and 10 A Load)
GUID-20230502-SS0I-K503-MZWH-CKC93LH1PCJ1-low.pngFigure 4-8 Inductor Current in Buck-Boost Region (VIN=16 V and 10 A Load)
GUID-20230502-SS0I-3VPL-CH68-KK5CFPDQQLRF-low.pngFigure 4-10 Inductor Current in Buck Region (VIN=30 V and 10 A Load)