TIDUED7A November   2018  – November 2022

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Highlighted Products
      1. 2.2.1 LM5155-Q1
      2. 2.2.2 TPS92610-Q1, TPS92611-Q1
    3. 2.3 System Design Theory
      1. 2.3.1  PCB and Form Factor
      2. 2.3.2  Input Protection
      3. 2.3.3  EMI Filter
      4. 2.3.4  LM5155-Q1 Voltage Regulator
      5. 2.3.5  Tail Light (2x TPS92611-Q1)
      6. 2.3.6  Stop Light (2x TPS92610-Q1)
      7. 2.3.7  Turn Light (TPS92610-Q1)
      8. 2.3.8  Backup Light
      9. 2.3.9  Enabling Light Functions
      10. 2.3.10 Diagnostic
      11. 2.3.11 LED Load
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware
    2. 3.2 Testing and Results
      1. 3.2.1 Startup / Shutdown
      2. 3.2.2 Steady State Operation
      3. 3.2.3 Load Transient Response
      4. 3.2.4 Stability
      5. 3.2.5 Efficiency
      6. 3.2.6 Electromagnetic Compatibility (EMC)
        1. 3.2.6.1 Conducted Emissions
        2. 3.2.6.2 Radiated Emissions
      7. 3.2.7 Thermal Performance
  9. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  10. 5Related Documentation
  11. 6Trademarks
  12. 7About the Author
  13. 8Revision History

2.3.2 Input Protection

In this reference design, reverse polarity protection is implemented by using Schottky diodes D1 through D4 on the input power lines as shown in Figure 2-5. The diodes are acting as an OR-ing circuit, which provides power to the pre-voltage regulator if one or more power rails get active.

For transient protection, a transient voltage suppressor (TVS) diode D5 is placed at the input after the reverse polarity protection to clamp the voltage. However, the LM5155-Q1 supports up to 45-V input voltage.

Resistors R6 through R9 are placed to sink reverse current of the Schottky diodes.

GUID-B7F08DAC-E6EC-4852-B7A1-A93C15F6FFDF-low.gifFigure 2-5 Schematic Input Protection