SNVSA15B December   2013  – December 2015 LP8557

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Function and Configurations
  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  Boost Converter Electrical Characteristics
    7. 7.7  LED Driver Electrical Characteristics (LED1 To LED6 Pins)
    8. 7.8  PWM Interface Characteristics (PWM Pin)
    9. 7.9  Logic Interface Characteristics (PWM, FSET/SDA, ISET/SCL Pins)
    10. 7.10 I2C Serial Bus Timing Parameters (SDA, SCL)
    11. 7.11 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 Boost Converter Overview
        1. 8.3.1.1 Operation
        2. 8.3.1.2 Adaptive Boost Output Voltage Control
      2. 8.3.2 Brightness Control
        1. 8.3.2.1 PWM Input Duty Measurement
        2. 8.3.2.2 BRTMODE = 00b
        3. 8.3.2.3 BRTMODE = 01b
        4. 8.3.2.4 BRTMODE = 10b
        5. 8.3.2.5 BRTMODE = 11b
        6. 8.3.2.6 Hybrid PWM & I Dimming Control
        7. 8.3.2.7 Phase Shift PWM Scheme
      3. 8.3.3 Slope and Advanced Slope
      4. 8.3.4 LED String Count Auto Detection
      5. 8.3.5 EMI Reduction Schemes
      6. 8.3.6 Fault Detection
        1. 8.3.6.1 LED Short Detection
        2. 8.3.6.2 LED OPEN* Detection
        3. 8.3.6.3 Undervoltage Detection
        4. 8.3.6.4 Thermal Shutdown
        5. 8.3.6.5 Boost Overcurrent Protection
        6. 8.3.6.6 Boost Overvoltage Protection
        7. 8.3.6.7 Boost Undervoltage Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Active Mode
    5. 8.5 Programming
      1. 8.5.1 I2C-Compatible Serial Bus Interface
        1. 8.5.1.1 Interface Bus Overview
        2. 8.5.1.2 Start and Stop Conditions
        3. 8.5.1.3 Data Transactions
        4. 8.5.1.4 Acknowledge Cycle
        5. 8.5.1.5 Acknowledge After Every Byte Rule
        6. 8.5.1.6 Control Register Write Cycle
        7. 8.5.1.7 Control Register Read Cycle
        8. 8.5.1.8 Register Read and Write Detail
    6. 8.6 Register Maps
      1. 8.6.1 Register Bit Descriptions
        1. 8.6.1.1  COMMAND
        2. 8.6.1.2  STATUS
        3. 8.6.1.3  BRTLO
        4. 8.6.1.4  BRTHI
        5. 8.6.1.5  CONFIG
        6. 8.6.1.6  CURRENT
        7. 8.6.1.7  PGEN
        8. 8.6.1.8  BOOST
        9. 8.6.1.9  LEDEN
        10. 8.6.1.10 STEP
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Designing With LP8557
        1. 9.1.1.1 Setting Boost Switching and PWM Dimming Frequencies
        2. 9.1.1.2 Setting Boost Compensation
        3. 9.1.1.3 Setting Full-Scale Led Current
      2. 9.1.2 Designing With LP8557I
        1. 9.1.2.1 Setting Boost Switching Frequency
        2. 9.1.2.2 Setting Boost Compensation
        3. 9.1.2.3 Setting PWM Dimming Frequency
        4. 9.1.2.4 Setting Full-Scale LED Current
    2. 9.2 Typical Applications
      1. 9.2.1 LP8557 PWM-Only Option
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Boost Output Capacitor Selection
          2. 9.2.1.2.2 Schottky Diode Selection
          3. 9.2.1.2.3 Inductor Selection
          4. 9.2.1.2.4 Boost Input andVDD Capacitor Selection
        3. 9.2.1.3 Application Curves
      2. 9.2.2 LP8557I PWM and I2C Device Option
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Boost Output Capacitor Placement
      2. 11.1.2 Schottky Diode Placement
      3. 11.1.3 Inductor Placement
      4. 11.1.4 Boost Input and VDD Capacitor Placement
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Related Links
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

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12 Device and Documentation Support

12.1 Device Support

12.1.1 Third-Party Products Disclaimer

TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.

12.2 Related Links

The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy.

Table 13. Related Links

PARTS PRODUCT FOLDER SAMPLE & BUY TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY
LP8557 Click here Click here Click here Click here Click here
LP85571 Click here Click here Click here Click here Click here

12.3 Community Resources

The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use.

    TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers.
    Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support.

12.4 Trademarks

E2E is a trademark of Texas Instruments.

All other trademarks are the property of their respective owners.

12.5 Electrostatic Discharge Caution

esds-image

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

12.6 Glossary

SLYZ022 — TI Glossary.

This glossary lists and explains terms, acronyms, and definitions.