SNVA966 July   2020  – MONTH  LP8864-Q1 , LP8864S-Q1 , LP8866-Q1 , LP8866S-Q1

 

  1.   Trademarks
  2. 1Fault Handling Routine
  3. 2Different Fault and Diagnostic Handling Method Recommendation
    1. 2.1 Different Fault Handling Method
      1. 2.1.1 System Brightness Derating
      2. 2.1.2 System-Level Unrecoverable Critical Fault
      3. 2.1.3 System-Level Sustainable Fault
    2. 2.2 Different Diagnostic Wrong Information Handling Method
      1. 2.2.1 System-Level Critical Wrong Diagnostic Information
      2. 2.2.2 System Level Sustainable Wrong Diagnostic Information
  4. 3Summary
  5.   A Fault-Related Functions
    1.     A.1 Protection and Fault Detections
      1.      A.1.1 Supply Faults
        1.       A.1.1.1 VIN Undervoltage Faults (VINUVLO)
        2.       16
        3.       A.1.1.2 VIN Overvoltage Faults (VINOVP)
        4.       A.1.1.3 VDD Undervoltage Faults (VDDUVLO)
        5.       A.1.1.4 VIN OCP Faults (VINOCP)
        6.       A.1.1.5 Charge Pump Faults (CPCAP, CP)
        7.       A.1.1.6 Boost Sync Clock Invalid Faults (BSTSYNC)
        8.       A.1.1.7 CRC Error Faults (CRCERR)
      2.      A.1.2 Boost Faults
        1.       A.1.2.1 Boost Overvoltage Faults (BSTOVPL, BSTOVPH)
        2.       A.1.2.2 Boost Overcurrent Faults (BSTOCP)
        3.       A.1.2.3 LEDSET Resistor Missing Faults (LEDSET)
        4.       A.1.2.4 MODE Resistor Missing Faults (MODESEL)
        5.       A.1.2.5 FSET Resistor Missing Faults (FSET)
        6.       A.1.2.6 ISET Resistor Out of Range Faults (ISET)
        7.       A.1.2.7 Thermal Shutdown Faults (TSD)
      3.      A.1.3 LED Faults
        1.       A.1.3.1 Open LED Faults (OPEN_LED)
        2.       A.1.3.2 Short LED Faults (SHORT_LED)
        3.       A.1.3.3 LED Short to GND Faults (GND_LED)
        4.       A.1.3.4 Invalid LED String Faults (INVSTRING)
        5.       A.1.3.5 I2C Timeout Faults
      4.      A.1.4 Overview of the Fault and Protection Schemes
    2.     A.2 Programming Examples
      1.      A.2.1 Clearing Fault Interrupts
      2.      A.2.2 Disabling Fault Interrupts
      3.      A.2.3 Diagnostic Registers

2.1.1 System Brightness Derating

The following faults can potentially be recovered by system brightness derating:

  • VIN Undervoltage Faults (VINUVLO)
  • VDD Undervoltage Faults (VDDUVLO)
  • Charge Pump Faults (CACAP, CP)
  • Boost Overcurrent Faults (BSTOCP)
  • Thermal Shutdown Faults (TSD)

These power-related faults are mostly caused by the marginal behavior of the power related blocks. Derating the brightness will decrease the loading of the power blocks. It might help to recover those faults.

The brightness derating action could be removed after a certain period (for example, first time attempt after 1 minute, another attempt after 5 minutes). If no fault after brightness derating action is removed, the system could return to normal.