SLVSHI2A February   2024  – April 2024 LP5867

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7.     14
    8. 6.7 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Time-Multiplexing Matrix
      2. 7.3.2 Analog Dimming (Current Gain Control)
        1. 7.3.2.1 Global 3-Bits Maximum Current (MC) Setting
        2. 7.3.2.2 3 Groups of 7-Bits Color Current (CC) Setting
        3. 7.3.2.3 Individual 8-bit Dot Current (DC) Setting
      3. 7.3.3 PWM Dimming
        1. 7.3.3.1 Individual 8-Bit / 16-Bit PWM for Each LED Dot
        2. 7.3.3.2 Programmable Groups of 8-Bit PWM Dimming
        3. 7.3.3.3 8-Bit PWM for Global Dimming
      4. 7.3.4 ON and OFF Control
      5. 7.3.5 Data Refresh Mode
      6. 7.3.6 Full Addressable SRAM
      7. 7.3.7 Protections and Diagnostics
        1. 7.3.7.1 LED Open Detection
        2. 7.3.7.2 LED Short Detection
        3. 7.3.7.3 Thermal Shutdown
        4. 7.3.7.4 UVLO (Under Voltage Lock Out)
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
      1. 7.5.1 Interface Selection
      2. 7.5.2 I2C Interface
        1. 7.5.2.1 I2C Data Transactions
        2. 7.5.2.2 I2C Data Format
        3. 7.5.2.3 Multiple Devices Connection
      3. 7.5.3 Programming
        1. 7.5.3.1 SPI Data Transactions
        2. 7.5.3.2 SPI Data Format
        3. 7.5.3.3 Multiple Devices Connection
    6. 7.6 Register Maps
  9. 8 Register Maps
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Application
      2. 9.2.2 Design Requirements
      3. 9.2.3 Detailed Design Procedure
        1. 9.2.3.1 Program Procedure
      4. 9.2.4 Application Performance Plots
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 VDD Input Supply Recommendations
      2. 9.3.2 VLED Input Supply Recommendations
      3. 9.3.3 VIO Input Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

7.3.7.1 LED Open Detection

The LP5867 includes LED open detection (LOD) for the fault caused by any opened LED dot. The threshold for LED open is 0.25V typical. LED open detection is only performed when PWM ≥ 25 (Mode 1 and Mode 2) or PWM ≥ 6400 (Mode 3) and voltage on CSn is detected lower than open threshold for continuously 4 sub-periods.

Figure 7-11 shows the detection circuit of LOD function. When open fault is detected, 'Global_LOD' bit in Fault_state register is set to 1 and detailed fault state for each LED is also monitored in register Dot_lodx (x = 0, 1, … , 20). All open fault indicator bits can be cleared by setting LOD_clear = 0Fh after the open condition is removed.

LOD removal function can be enabled by setting 'LOD_removal' bit in Dev_config2 register to 1. This function turns off the current sink of the open channel when scanning to the line where the opened LED is included.

GUID-20230822-SS0I-P5BN-LKMD-V62NDNPH7PHR-low.svg Figure 7-11 LOD Circuits