SNVSB83B June   2019  – January 2020 LP8867-Q1 , LP8869-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Schematic
    2.     LED Backlight Efficiency
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics
    6. 7.6  Internal LDO Electrical Characteristics
    7. 7.7  Protection Electrical Characteristics
    8. 7.8  Current Sinks Electrical Characteristics
    9. 7.9  PWM Brightness Control Electrical Characteristics
    10. 7.10 Boost and SEPIC Converter Characteristics
    11. 7.11 Logic Interface Characteristics
    12. 7.12 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Integrated DC-DC Converter
        1. 8.3.1.1 DC-DC Converter Parameter Configuration
          1. 8.3.1.1.1 Switching Frequency
          2. 8.3.1.1.2 Spread Spectrum and External SYNC
          3. 8.3.1.1.3 Recommended Component Value and Internal Parameters
          4. 8.3.1.1.4 DC-DC Converter Switching Current Limit
          5. 8.3.1.1.5 DC-DC Converter Light Load Mode
        2. 8.3.1.2 Adaptive Voltage Control
          1. 8.3.1.2.1 Using Two-Divider
          2. 8.3.1.2.2 Using T-Divider
          3. 8.3.1.2.3 Feedback Capacitor
      2. 8.3.2 Internal LDO
      3. 8.3.3 LED Current Sinks
        1. 8.3.3.1 LED Output Configuration
        2. 8.3.3.2 LED Current Setting
        3. 8.3.3.3 Brightness Control
      4. 8.3.4 Power-Line FET Control
      5. 8.3.5 LED Current Dimming With External Temperature Sensor
      6. 8.3.6 Fault Detections and Protection
        1. 8.3.6.1 Supply Fault and Protection
          1. 8.3.6.1.1 VIN Undervoltage Fault (VIN_UVLO)
          2. 8.3.6.1.2 VIN Overvoltage Fault (VIN_OVP)
          3. 8.3.6.1.3 VIN Overcurrent Fault (VIN_OCP)
        2. 8.3.6.2 Boost Fault and Protection
          1. 8.3.6.2.1 Boost Overvoltage Fault (BST_OVP)
          2. 8.3.6.2.2 SW Overvoltage Fault (SW_OVP)
        3. 8.3.6.3 LED Fault and Protection (LED_OPEN and LED_SHORT)
        4. 8.3.6.4 Thermal Fault and Protection (TSD)
        5. 8.3.6.5 Overview of the Fault and Protection Schemes
    4. 8.4 Device Functional Modes
      1. 8.4.1 STANDBY State
      2. 8.4.2 SOFT START State
      3. 8.4.3 BOOST START State
      4. 8.4.4 NORMAL State
      5. 8.4.5 FAULT RECOVERY State
      6. 8.4.6 State Diagram and Timing Diagram for Start-up and Shutdown
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Typical Application for 4 LED Strings
      2. 9.2.2 Design Requirements
      3. 9.2.3 Detailed Design Procedure
        1. 9.2.3.1 Inductor Selection
        2. 9.2.3.2 Output Capacitor Selection
        3. 9.2.3.3 Input Capacitor Selection
        4. 9.2.3.4 LDO Output Capacitor
        5. 9.2.3.5 Diode
      4. 9.2.4 Application Curves
      5. 9.2.5 SEPIC Mode Application
        1. 9.2.5.1 Design Requirements
        2. 9.2.5.2 Detailed Design Procedure
          1. 9.2.5.2.1 Inductor
          2. 9.2.5.2.2 Diode
          3. 9.2.5.2.3 Capacitor C1
        3. 9.2.5.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.6.5 Overview of the Fault and Protection Schemes

A summary of the LP886x-Q1 fault detection behavior is shown in Table 3. Detected faults (excluding LED open or short) cause device to enter FAULT RECOVERY state. In FAULT_RECOVERY the DC-DC and LED current sinks of the device are disabled, and the FAULT pin is pulled low. The device will exit FAULT RECOVERY mode after 100 ms and try the start-up sequence again. When recovery is successful and device enters into NORMAL state, the FAULT pin is released high.

Table 3. Fault Detections

FAULT/
PROTECTION 		FAULT NAME CONDITION FAULT PIN Enter FAULT_
RECOVERY
STATE		 ACTIVE STATE ACTION
VIN overvoltage protection VIN_OVP VIN > 43 V
Yes Yes SOFT START, BOOST START, NORMAL Device enters into FAULT RECOVERY state, and restarts after 100 ms
VIN undervoltage protection VIN_UVLO Effective when VIN < 3.85 V
Released when VIN >4 V 		Yes Yes SOFT START, BOOST START, NORMAL Device enters into FAULT RECOVERY state, and restarts after 100 ms
VIN overcurrent protection VIN_OCP VIN-VSENSE_N > 160mV Yes Yes SOFT START, BOOST START, NORMAL Device enters into FAULT RECOVERY state, and restarts after 100 ms
Open LED fault LED _OPEN Adaptive Voltage is max. and
any OUTx voltage < 0.9 V		 Yes No NORMAL Open string is removed from the DC-DC voltage control loop and output is disabled.
Fault pin low could be released by toggling VDDIO/EN pin, If VDDIO/EN is low for a period of 2 µs to 20 µs, LEDs are turned off for this period but device stays in NORMAL.
Shorted LED fault LED_SHORT One of OUTx voltage is [0.9 V, 1.9 V] and
any OUTx voltage > 6 V		 Yes No NORMAL Short string is removed from the DC-DC voltage control loop and output is disabled.
Fault pin low could be released by toggling VDDIO/EN pin, If VDDIO/EN is low for a period of 2 µs to 20 µs, LEDs are turned off for this period but device stays NORMAL.
Boost overvoltage protection BST_OVP VFB > 2.3 V Yes Yes NORMAL Fault is detected if boost overvoltage condition duration is more than 560 ms
Device enters into FAULT RECOVERY state, and restarts after 100 ms
SW overvoltage protection SW_OVP VSW > 49 V Yes Yes SOFT START, BOOST START, NORMAL Device enters into FAULT RECOVERY state, and restarts after 100 ms
Thermal protection TSD Effective when Tj > 165 ºC
Released when Tj < 145 ºC		 Yes Yes SOFT START, BOOST START, NORMAL Device enters into FAULT RECOVERY state, and restarts until TSD fault is released