SNVSA21H May   2014  – April 2025 LP8860-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5.   Device Comparison Table
  6. 4 Pin Configuration and Functions
    1.     Pin Functions
  7. 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  Current Sinks Electrical Characteristics
    7. 5.7  Boost Converter Characteristics
    8. 5.8  Logic Interface Characteristics
    9. 5.9  VIN Undervoltage Protection (VIN_UVLO)
    10. 5.10 VDD Undervoltage Protection (VDD_UVLO)
    11. 5.11 VIN Overvoltage Protection (VIN_OVP)
    12. 5.12 VIN Overcurrent Protection (VIN_OCP)
    13. 5.13 Power-Line FET Control Electrical Characteristics
    14. 5.14 External Temp Sensor Control Electrical Characteristics
    15. 5.15 I2C Serial Bus Timing Parameters (SDA, SCLK)
    16. 5.16 SPI Timing Requirements
    17. 5.17 Typical Characteristics
  8. 6 Detailed Description
    1. 6.1 Overview
      1. 6.1.1 Boost Controller
      2. 6.1.2 LED Output Configurations
      3. 6.1.3 Display Mode
      4. 6.1.4 Cluster Mode
      5. 6.1.5 Hybrid Dimming
      6. 6.1.6 Charge Pump and Square Waveform (SQW) Output
      7. 6.1.7 Power-Line FET
      8. 6.1.8 Protection Features
      9. 6.1.9 Advanced Thermal Protection Features
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Clock Generation
        1. 6.3.1.1 LED PWM Clock Generation With VSYNC
        2. 6.3.1.2 LED PWM Frequency and Resolution
      2. 6.3.2 Brightness Control (Display Mode)
        1. 6.3.2.1 PWM Input Duty Cycle Based Control
        2. 6.3.2.2 Brightness Register Control
        3. 6.3.2.3 PWM Input Duty × Brightness Register
        4. 6.3.2.4 PWM-Input Direct Control
        5. 6.3.2.5 Brightness Slope
        6. 6.3.2.6 LED Dimming Methods
        7. 6.3.2.7 PWM Calculation Data Flow for Display Mode
      3. 6.3.3 LED Output Modes and Phase Shift PWM (PSPWM) Scheme
      4. 6.3.4 LED Current Setting
      5. 6.3.5 Cluster Mode
      6. 6.3.6 Boost Controller
      7. 6.3.7 Charge Pump
      8. 6.3.8 Powerline Control FET
      9. 6.3.9 Protection and Fault Detection Modes
        1. 6.3.9.1 LED Fault Comparators and Adaptive Boost Control
        2. 6.3.9.2 LED Current Dimming With Internal Temperature Sensor
        3. 6.3.9.3 LED Current Limitation With External NTC Sensor
        4. 6.3.9.4 LED Current Dimming With External NTC Sensor
        5. 6.3.9.5 Protection Feature and Fault Summary
    4. 6.4 Device Functional Modes
      1. 6.4.1 Standby Mode
      2. 6.4.2 Active Mode
      3. 6.4.3 Fault Recovery State
      4. 6.4.4 Start-Up and Shutdown Sequences
    5. 6.5 Programming
      1. 6.5.1 EEPROM
      2. 6.5.2 Serial Interface
        1. 6.5.2.1 SPI Interface
        2. 6.5.2.2 I2C Serial Bus Interface
          1. 6.5.2.2.1 Interface Bus Overview
          2. 6.5.2.2.2 Data Transactions
          3. 6.5.2.2.3 Acknowledge Cycle
          4. 6.5.2.2.4 Acknowledge After Every Byte Rule
          5. 6.5.2.2.5 Addressing Transfer Formats
          6. 6.5.2.2.6 Control Register Write Cycle
          7. 6.5.2.2.7 Control Register Read Cycle
    6. 6.6 Register Maps
      1. 6.6.1 Register Bit Explanations
        1. 6.6.1.1  Display/Cluster1 Brightness Control MSB
        2. 6.6.1.2  Display/Cluster1 Brightness Control LSB
        3. 6.6.1.3  Display/Cluster1 Output Current MSB
        4. 6.6.1.4  Display/Cluster1 Output Current LSB
        5. 6.6.1.5  Cluster2 Brightness Control MSB
        6. 6.6.1.6  Cluster2 Brightness Control LSB
        7. 6.6.1.7  Cluster2 Output Current
        8. 6.6.1.8  Cluster3 Brightness Control MSB
        9. 6.6.1.9  Cluster3 Brightness Control LSB
        10. 6.6.1.10 Cluster3 Output Current
        11. 6.6.1.11 Cluster4 Brightness Control MSB
        12. 6.6.1.12 Cluster4 Brightness Control LSB
        13. 6.6.1.13 Cluster4 Output Current
        14. 6.6.1.14 Configuration
        15. 6.6.1.15 Status
        16. 6.6.1.16 Fault
        17. 6.6.1.17 LED Fault
        18. 6.6.1.18 Fault Clear
        19. 6.6.1.19 Identification
        20. 6.6.1.20 Temp MSB
        21. 6.6.1.21 Temp LSB
        22. 6.6.1.22 Display LED Current MSB
        23. 6.6.1.23 Display LED Current LSB
        24. 6.6.1.24 Display LED PWM MSB
        25. 6.6.1.25 Display LED PWM LSB
        26. 6.6.1.26 EEPROM Control
        27. 6.6.1.27 EEPROM Unlock Code
      2. 6.6.2 EEPROM Bit Explanations
        1. 6.6.2.1  EEPROM Register 0
        2. 6.6.2.2  EEPROM Register 1
        3. 6.6.2.3  EEPROM Register 2
        4. 6.6.2.4  EEPROM Register 3
        5. 6.6.2.5  EEPROM Register 4
        6. 6.6.2.6  EEPROM Register 5
        7. 6.6.2.7  EEPROM Register 6
        8. 6.6.2.8  EEPROM Register 7
        9. 6.6.2.9  EEPROM Register 8
        10. 6.6.2.10 EEPROM Register 9
        11. 6.6.2.11 EEPROM Register 10
        12. 6.6.2.12 EEPROM Register 11
        13. 6.6.2.13 EEPROM Register 12
        14. 6.6.2.14 EEPROM Register 13
        15. 6.6.2.15 EEPROM Register 14
        16. 6.6.2.16 EEPROM Register 15
        17. 6.6.2.17 EEPROM Register 16
        18. 6.6.2.18 EEPROM Register 17
        19. 6.6.2.19 EEPROM Register 18
        20. 6.6.2.20 EEPROM Register 19
        21. 6.6.2.21 EEPROM Register 20
        22. 6.6.2.22 EEPROM Register 21
        23. 6.6.2.23 EEPROM Register 22
        24. 6.6.2.24 EEPROM Register 23
        25. 6.6.2.25 EEPROM Register 24
  9. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Applications
      1. 7.2.1 Typical Application for Display Backlight
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
          1. 7.2.1.2.1  Inductor Selection
          2. 7.2.1.2.2  Output Capacitor Selection
          3. 7.2.1.2.3  Input Capacitor Selection
          4. 7.2.1.2.4  Charge Pump Output Capacitor
          5. 7.2.1.2.5  Charge Pump Flying Capacitor
          6. 7.2.1.2.6  Diode
          7. 7.2.1.2.7  Boost Converter Transistor
          8. 7.2.1.2.8  Boost Sense Resistor
          9. 7.2.1.2.9  Power Line Transistor
          10. 7.2.1.2.10 Input Current Sense Resistor
          11. 7.2.1.2.11 Filter Component Values
            1. 7.2.1.2.11.1 Critical Components for Design
        3. 7.2.1.3 Application Performance Plots
      2. 7.2.2 Low VDD Voltage and Combined Output Mode Application
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
        3. 7.2.2.3 Application Performance Plots
      3. 7.2.3 High Output Voltage Application
        1. 7.2.3.1 Design Requirements
        2. 7.2.3.2 Detailed Design Procedure
        3. 7.2.3.3 Application Performance Plots
      4. 7.2.4 High Output Current Application
        1. 7.2.4.1 Design Requirements
        2. 7.2.4.2 Detailed Design Procedure
        3. 7.2.4.3 Application Performance Plots
      5. 7.2.5 Three-Channel Configuration Without Serial Interface
        1. 7.2.5.1 Design Requirements
        2. 7.2.5.2 Detailed Design Procedure
        3. 7.2.5.3 Application Performance Plots
      6. 7.2.6 Solution With Minimum External Components
        1. 7.2.6.1 Design Requirements
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  10. 8 Device and Documentation Support
    1. 8.1 Device Support
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Community Resources
    5. 8.5 Trademarks
  11. 9 Revision History
  12. 10Mechanical, Packaging, and Orderable Information

6.3.2.7 PWM Calculation Data Flow for Display Mode

Figure 6-9 shows the PWM calculation data flow for display mode. In PWM direct control mode most of the blocks are bypassed, and this flow chart does not apply.

LP8860-Q1 PWM Data Flow CalculationFigure 6-9 PWM Data Flow Calculation
Table 6-8 PWM Calculation Blocks
BLOCK NAMEDESCRIPTION
PWM detectorPWM detector block measures the duty cycle of the input PWM signal. Resolution depends on the input signal frequency. Hysteresis selection sets the minimum allowable change to the input. Smaller changes are ignored.
Brightness register16-bit register for brightness setting <DISP_CL1_BRT[15:0]>
Brightness mode controlBrightness control block gets 16-bit value from the PWM detector, and also 16-bit value from the brightness register <DISP_CL1_BRT[15:0]>. <BRT_MODE[1:0]> selects whether to use PWM input duty cycle value, the brightness register value or multiplication.
Temperature regulatorTemperature regulator reduces LED PWM duty cycle depending on internal and external temperature sensor.
See Section 6.3.9.2 and Section 6.3.9.3 for details
External temperature sensorExternal NTC temperature sensor
Internal temperature sensorInternal die temperature sensor
SloperSloper makes the smooth transition from one brightness value to another. Slope time can be adjusted from 0 ms to 511 ms with <PWM_SLOPE[2:0]> EEPROM bits.
Advanced sloperAdvanced slope makes brightness changes smoother for eye; see Section 6.3.2.5 for details
PWM and Current ControlHybrid PWM and Current dimming improves the optical efficiency of the LEDs by using PWM control with lower brightness values and current control with greater values. <EN_PWM_I> EEPROM bit enables Hybrid PWM and Current control. PWM dimming range can be set 12.5 to 50% of the brightness range with <GAIN_CTRL[2:0]> EEPROM bits. Current slope can be adjusted by using the <I_SLOPE[2:0]> EEPROM bits. See Section 6.3.2.6 for details
DitherWith dithering the output resolution can be further increased. This way the brightness change steps are not visible to eye. The amount of dithering is 0 to 4 bits, and is selected with <DITHER[2:0]> EEPROM bits.
PWM comparatorPWM comparator compares the PWM counter output to the value received from the dither block. Output of the PWM comparator directly controls the LED current sinks. If Phase Shift PWM (PSPWM) mode is used, the PWM counter values for each LED output are modified by summing an offset value to create different phases.
PWM counterOverflowing 16-bit PWM counter creates new PWM cycle. Step for incrementation is defined by <PWM_FREQ[3:0]> and <PWM_RESOLUTION[1:0]> bits, see Table 6-3.