TIDUES6 August   2020  – MONTH 

 

  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 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 DRV8906-Q1
      2. 2.3.2 DRV8873-Q1
      3. 2.3.3 TPS1HB16-Q1
      4. 2.3.4 LM2904B-Q1
      5. 2.3.5 TLIN1028-Q1
    4. 2.4 System Design Theory
      1. 2.4.1 Mirror XY and LED Driver
      2. 2.4.2 Mirror Fold Driver
      3. 2.4.3 Mirror Heater Driver for Defogging and De-icing
      4. 2.4.4 Electrochromic Mirror Driver
        1. 2.4.4.1 Sallen-Key Low-Pass Filter
        2. 2.4.4.2 High-Current Buffer Amplifier
        3. 2.4.4.3 Buffer Amplifier Stability for Very-Large Capacitive Loads
        4. 2.4.4.4 Fast Discharge of Large Capacitive Load
      5. 2.4.5 SBC - LIN Communication Interface and System Supply
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
      2. 3.2.2 Test Results
        1. 3.2.2.1 Reverse Battery Protection
        2. 3.2.2.2 X&Y Motors and LED Driver
        3. 3.2.2.3 Thermal Performance
  9. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 Altium Project
    4. 4.4 Gerber Files
    5. 4.5 Assembly Drawings
  10. 5Software Files
  11. 6Related Documentation
    1. 6.1 Trademarks
    2. 6.2 Third-Party Products Disclaimer
  12. 7Terminology

2.4.1 Mirror XY and LED Driver

The mirror X&Y angle adjust motors and the LEDs are driven by the DRV8906-Q1. The DRV8906-Q1 has a total of 6 half-bridges. Three of the 6 half-bridges drive the three LEDs and the rest of the half-bridges drive the two brushed DC motors used for X&Y angle adjust.

Figure 2-7 shows the DRV8906-Q1 configuration schematic. To save one half-bridge, the two brushed DC motors are connected in a sequential configuration. In this configuration, the two motors share one half-bridge since the two motors will never be driven simultaneously.

The decoupling capacitors (C1, C2, C3, C4) values are selected based on the recommended values on the data sheet. The nFAULT pin is open drain so a 10-kΩ pullup resistor pulls nFAULT to VDD. Each of the three LEDs have a 200-Ω resistor in series to limit the current.

GUID-527CF519-BC90-4D43-A971-23BCF00130E9-low.gifFigure 2-7 DRV8906-Q1 Configuration Schematic