JAJU617A October   2018  – May 2022

 

  1.   概要
  2.   Resources
  3.   特長
  4.   アプリケーション
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagrams
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 DLP3030-Q1
      2. 2.3.2 DLPC120-Q1
      3. 2.3.3 TMS320F28023
    4. 2.4 System Design Theory
      1. 2.4.1 Head-up Display Parameter Design and Tradeoffs
        1. 2.4.1.1 Field of View and Eyebox
        2. 2.4.1.2 Resolution
        3. 2.4.1.3 Virtual Image Distance
      2. 2.4.2 Picture Generation Unit Design Decisions
        1. 2.4.2.1 Etendue Efficiency Match
        2. 2.4.2.2 Aperture Size: Selecting f/# of Optics
        3. 2.4.2.3 Thermal Design
        4. 2.4.2.4 LED Selection Summary
      3. 2.4.3 Design Summary
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
      2. 3.1.2 Software
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
      2. 3.2.2 Test Results
  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 Cadence Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  10. 5Software Files
  11. 6Related Documentation
    1. 6.1 Trademarks
  12. 7Terminology
  13. 8Revision History

3.2.2 Test Results

Power consumption is primarily determined by luminous output. Maximum brightness of 90 lumens requires about 7.1 W of power, but this is only needed on extremely sunny days. Nominal HUD brightness will be closer to 25 lumens, which only requires about 2.9 W of power.

Table 3-3 Typical Power Consumption vs Luminous Output
HUD BrightnessCalculated Luminous OutputMeasured System Power (W)
Max Brightness90 lumens7.1
Medium Brightness75 lumens5.9
Low Brightness25 lumens2.9
Min Brightness0.018 lumens1.8

To support the lowest brightness ranges, around 1/5000th of max brightness, the LED driver must create very small, short pulses of light. The LED driver included in this design supports LED pulses below 1 µs. Figure 3-1 below shows a short pulse on the output of the photodiode signal, measured at TP6.

For more information on the LED driver and dimming functionality, please see the Enabling the Next Generation of Automotive Head-Up Display Systems application note.

GUID-9C777EC0-8DF0-493F-8764-17FF0A08EB0E-low.pngFigure 3-1 Shortest LED Pulse of 952 ns