JAJSNB3 September   2023 LP5813

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Revision History
  6. 5 Device Comparison
  7. 6 Pin Configuration and Functions
  8. 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 Timing Requirements
  9. 8 Typical Characteristics
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Synchronous Boost Converter
        1. 9.3.1.1 Undervoltage Lockout
        2. 9.3.1.2 Enable and Soft Start
        3. 9.3.1.3 Switching Frequency
        4. 9.3.1.4 Current Limit Operation
        5. 9.3.1.5 Boost PWM Mode
        6. 9.3.1.6 Boost PFM Mode
        7. 9.3.1.7 Pass-Through Mode
      2. 9.3.2 Time-cross-multiplexing (TCM) scheme
        1. 9.3.2.1 Direct drive mode
        2. 9.3.2.2 TCM drive mode
        3. 9.3.2.3 Mix drive mode
        4. 9.3.2.4 Ghosting elimination
      3. 9.3.3 Analog Dimming
      4. 9.3.4 PWM Dimming
      5. 9.3.5 Autonomous Animation Engine Control
        1. 9.3.5.1 Animation Engine Pattern
        2. 9.3.5.2 Sloper
        3. 9.3.5.3 Animation Engine Unit (AEU)
        4. 9.3.5.4 Animation Pause Unit (APU)
      6. 9.3.6 Protections and Diagnostics
        1. 9.3.6.1 Overvoltage Protection
        2. 9.3.6.2 Output Short-to-Ground Protection
        3. 9.3.6.3 LED Open Detections
        4. 9.3.6.4 LED Short Detections
        5. 9.3.6.5 Thermal Shutdown
    4. 9.4 Device Functional Modes
    5. 9.5 Programming
    6. 9.6 Register Map Table
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Application
      2. 10.2.2 Design Parameters
      3. 10.2.3 Detailed Design Procedure
        1. 10.2.3.1 Inductor Selection
        2. 10.2.3.2 Output Capacitor Selection
        3. 10.2.3.3 Input Capacitor Selection
        4. 10.2.3.4 Program Procedure
        5. 10.2.3.5 Programming Example
      4. 10.2.4 Application Performance Plots
    3. 10.3 Power Supply Recommendations
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
    2. 11.2 ドキュメントの更新通知を受け取る方法
    3. 11.3 サポート・リソース
    4. 11.4 Trademarks
    5. 11.5 静電気放電に関する注意事項
    6. 11.6 用語集
  13. 12Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

9.3.1.4 Current Limit Operation

The LP5813 uses a valley current limit sensing scheme. The inductor current is detected during the switching off-time, by sensing the voltage across the synchronous rectifier.

When the load current increases, such that the inductor current is above the current limit within the whole switching cycle , the off-time increases to discharge the inductor current. The current decreases below the limit before the next on-time. When the current limit is reached, the output voltage decreases if the load current continually increases.

The maximum continuous output current (IOUT(CL)), before entering current limit (CL) operation, can be defined by Equation 1.

Equation 1. I O U T ( C L ) = 1 - D × I L I M + 1 2 ∆ I L P - P

where

  • D is the duty cycle
  • ΔIL(P-P) is the inductor ripple current

The duty cycle can be estimated by Equation 2.

Equation 2. D = 1 - V I N × η V O U T

where

  • VOUT is the output voltage of the boost converter
  • VIN is the input voltage of the boost converter
  • η is the efficiency of the converter, use 90% for most applications

The peak-to-peak inductor ripple current is calculated by Equation 3.

Equation 3. ∆ILP-P=VIN×DL×fSW

where

  • L is the inductance value of the inductor
  • fSW is the switching frequency
  • D is the duty cycle
  • VIN is the input voltage of the boost converter