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

2.2.1 System-Level Critical Wrong Diagnostic Information

Incorrect diagnostic information might also indicate some critical faults which could not be directly detected by fault detection mechanism of the chip. These include:

  • FSM_LIVE_STATUS is always not 10h (NORMAL) when the FAULT pin is not pulled low
  • PWM_INPUT_STATUS is not matched with system input
  • PWM_OUTPUT_STATUS is not matched with system input
  • LED_CURRENT_STATUS is not matched with system input

If any of these critical diagnostic information is wrong, TI recommends power cycling the chip. Do not continue working under these situations.