TIDT445 May   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Load Transient Test Circuit
    3. 2.3 Highlighted Products
      1. 2.3.1 LM5137F-Q1 Overview
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1. 3.3.1 Efficiency Data
      2. 3.3.2 Efficiency Graphs
      3. 3.3.3 Output Voltage Ripple
      4. 3.3.4 Thermal Images
      5. 3.3.5 Bode Plots
      6. 3.3.6 Load Transients
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
      3. 4.1.3 Altium Project
      4. 4.1.4 Gerber Files
      5. 4.1.5 Assembly Drawings
    2. 4.2 Documentation Support
    3. 4.3 Support Resources
    4. 4.4 Trademarks
  11. 5About the Author

1 System Description

The cabin integration architecture supports both automotive infotainment and intelligent driving features, providing greater integration and flexibility in modular design compared to the traditional cabin discrete architecture. Supports self-driving at L2+ level and above, while meeting both cabin and intelligent drive module capacity requirements. To achieve these features, a high-end processor with more than 400W of power is required. The power rail that powers the processor presents a design challenge, delivering high power while meeting requirements for efficiency, ripple, transient loads, thermal performance and functional safety.

The reference design describes a four-phase interleaved buck converter which can be used in ADAS and IVI application. The converter operates over a wide range of 6.5V to 36V to deliver 4.5V regular outputs with better than 1% set-point accuracy at load currents up to 42A per output. Applying dynamic phase shedding, the converter shows good performance at light load. The converter can achieve as high as 81% efficiency at 15mA per output. With peak current control mode, the converter only has ±8.3% output voltage vibration when output current jumps from 21A to 86A in 1μs.

The LM5137F-Q1 is stackable, two LM5137F-Q1 in the same package are daisy chained together into a four-phase interleaved voltage regulator, with the first controller as the primary controller and the second as the secondary controller. In the configuration, the COMP1 and COMP2 of the two controllers are connected together, all outputs are connected together to maintain the switching frequency. Four-phase interleaving effectively reduces ripple current compared to single-phase controllers, thus reducing ripple voltage of output capacitors.