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

2.3 Interconnection of the Power Stages

Apart from the similar components for power stages, the individual power stage needs some interconnection between each other to make sure proper load sharing and to avoid phase overloads during the parallel operation of the converters. Thus, the Table 2-1 shows the several pins functions which need to be shared between the devices.

Table 2-1 Shared Pins
Pin function Pin Name Comment
Softstart SS/ATRK Shared soft-start capacitor
Compensation COMP Shared compensations network
Enable / undervoltage lock out EN/UVLO Same voltage level
Feedback FB Shared voltage divider circuit
Output Voltage VOUT Shared output
Input Voltage VIN Shared input
Bias Voltage BIAS Same voltage level

Moreover, there are some other pins that need to be set as shown in Table 2-2 for accurate parallel operation.

Table 2-2 Other Pins
Pin function Pin Name Comment
RT RT Must use the same value for all devices
External clock SYNC To make sure a good load balancing the clock must be phase shifted by 360/n [n = Number of power stages]
Slope Compensation SLOPE Must use the same value for all devices