SNVSCC4A October   2023  – September 2024 LP5811

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Synchronous Boost Converter
        1. 6.3.1.1 Undervoltage Lockout
        2. 6.3.1.2 Enable and Soft Start
        3. 6.3.1.3 Switching Frequency
        4. 6.3.1.4 Current Limit Operation
        5. 6.3.1.5 Boost PWM Mode
        6. 6.3.1.6 Boost PFM Mode
      2. 6.3.2 Analog Dimming
      3. 6.3.3 PWM Dimming
      4. 6.3.4 Autonomous Animation Engine Control
        1. 6.3.4.1 Animation Engine Pattern
        2. 6.3.4.2 Sloper
        3. 6.3.4.3 Animation Engine Unit (AEU)
        4. 6.3.4.4 Animation Pause Unit (APU)
      5. 6.3.5 Protections and Diagnostics
        1. 6.3.5.1 Overvoltage Protection
        2. 6.3.5.2 Output Short-to-Ground Protection
        3. 6.3.5.3 LED Open Detections
        4. 6.3.5.4 LED Short Detections
        5. 6.3.5.5 Thermal Shutdown
    4. 6.4 Device Functional Modes
    5. 6.5 Programming
    6. 6.6 Register Maps
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Application
      2. 7.2.2 Design Parameters
      3. 7.2.3 Detailed Design Procedure
        1. 7.2.3.1 Inductor Selection
        2. 7.2.3.2 Output Capacitor Selection
        3. 7.2.3.3 Input Capacitor Selection
        4. 7.2.3.4 Program Procedure
        5. 7.2.3.5 Programming Example
      4. 7.2.4 Application Performance Plots
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.5.3 LED Open Detections

The LP5811 integrates LED open detection (LOD) for the fault caused by any open LED. The threshold for LOD is 90 mV when max current is set as 25.5 mA, and 180 mV when max current is set as 51 mA. To have enough detection time, LOD can only be performed when the PWM setting of this LED is above 25. If the voltage on the cathode of this LED is lower than the LOD threshold in continuously 3 cycles, LED open of this LED is reported to the corresponding LOD_status register.

The LOD flags can be cleared by writing 1h to 'lod_clear' bit in Fault_Clear register. If the LED open status is removed, the related 'lod_status' bit is set to 0 automatically.

The 'lod_action' bit in Dev_config_12 register can determine the action once open fault is detected. When the 'lod_action' bit is set to 1h, the dot where LED open happens is turned off to avoid any unpredictable issue. When the 'lod_action' bit is 0, no additional action is taken after LOD is detected. LED open fault detection and action is only executed in NORMAL state.