SNVSCC4B October   2023  – December 2024 LP5811

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Synchronous Boost Converter
        1. 7.3.1.1 Undervoltage Lockout
        2. 7.3.1.2 Enable and Soft Start
        3. 7.3.1.3 Switching Frequency
        4. 7.3.1.4 Current Limit Operation
        5. 7.3.1.5 Boost PWM Mode
        6. 7.3.1.6 Boost PFM Mode
      2. 7.3.2 Analog Dimming
      3. 7.3.3 PWM Dimming
      4. 7.3.4 Autonomous Animation Engine Control
        1. 7.3.4.1 Animation Engine Pattern
        2. 7.3.4.2 Sloper
        3. 7.3.4.3 Animation Engine Unit (AEU)
        4. 7.3.4.4 Animation Pause Unit (APU)
      5. 7.3.5 Protections and Diagnostics
        1. 7.3.5.1 Overvoltage Protection
        2. 7.3.5.2 Output Short-to-Ground Protection
        3. 7.3.5.3 LED Open Detections
        4. 7.3.5.4 LED Short Detections
        5. 7.3.5.5 Thermal Shutdown
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
    6. 7.6 Register Maps
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Application
      2. 8.2.2 Design Parameters
      3. 8.2.3 Detailed Design Procedure
        1. 8.2.3.1 Inductor Selection
        2. 8.2.3.2 Output Capacitor Selection
        3. 8.2.3.3 Input Capacitor Selection
        4. 8.2.3.4 Program Procedure
        5. 8.2.3.5 Programming Example
      4. 8.2.4 Application Performance Plots
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.1.2 Enable and Soft Start

When the input voltage is above the UVLO rising threshold 1.8V and the EN pin is pulled to a voltage above 1.2V, the boost of LP5811 is enabled and starts up. At the beginning, the LP5811 charges the boost output capacitor with a constant current when the output voltage is below 0.4V. When the output voltage is charged above 0.4V, the LP5811 has capability to drive 200mA load. After the output voltage reaches the input voltage, the boost of LP5811 starts switching, and the output voltage continually ramps up to default voltage 3V. The typical start-up time is 450μs from EN pulled high to output reaching default voltage 3V, at the application that input voltage is 2.5V, output effective capacitance is 10μF, and no load. When the EN is below 0.42V, the internal enable comparator turns the device into shutdown mode. In the shutdown mode, the device is entirely turned off and the output is disconnected from input power supply.