JAJSJ94B September   2021  – August 2022 LM74722-Q1

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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 Switching Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Dual Gate Control (GATE, PD)
        1. 8.3.1.1 Reverse Battery Protection (A, C, GATE)
        2. 8.3.1.2 Load Disconnect Switch Control (PD)
        3. 8.3.1.3 Overvoltage Protection and Battery Voltage Sensing (VSNS, SW, OV)
      2. 8.3.2 Boost Regulator
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical 12-V Reverse Battery Protection Application
      1. 9.2.1 Design Requirements for 12-V Battery Protection
        1. 9.2.1.1 Automotive Reverse Battery Protection
          1. 9.2.1.1.1 Input Transient Protection: ISO 7637-2 Pulse 1
          2. 9.2.1.1.2 AC Super Imposed Input Rectification: ISO 16750-2 and LV124 E-06
          3. 9.2.1.1.3 Input Micro-Short Protection: LV124 E-10
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Design Considerations
        2. 9.2.2.2 Boost Converter Components (C2, C3, L1)
        3. 9.2.2.3 Input and Output Capacitance
        4. 9.2.2.4 Hold-Up Capacitance
        5. 9.2.2.5 Overvoltage Protection and Battery Monitor
        6. 9.2.2.6 MOSFET Selection: Blocking MOSFET Q1
        7. 9.2.2.7 MOSFET Selection: Load Disconnect MOSFET Q2
        8. 9.2.2.8 TVS Selection
      3. 9.2.3 Application Curves
    3. 9.3 What to Do and What Not to Do
  10. 10Power Supply Recommendations
    1. 10.1 Transient Protection
    2. 10.2 TVS Selection for 12-V Battery Systems
    3. 10.3 TVS Selection for 24-V Battery Systems
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 サポート・リソース
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, 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

9.2.2.1 Design Considerations

Table 9-1 summarizes the design parameters that must be known for designing an automotive reverse battery protection circuit with overvoltage cutoff. During power up, inrush current through MOSFET Q2 must be limited so that the MOSFET operates well within its SOA. Maximum load current, maximum ambient temperature, and thermal properties of the PCB determine the RDSON of the MOSFET Q2, and maximum operating voltage determines the voltage rating of the MOSFET Q2. Selection of MOSFET Q2 is determined mainly by the maximum operating load current, maximum ambient temperature, maximum frequency of AC super imposed voltage ripple, and ISO 7637-2 pulse 1 requirements. Overvoltage threshold is decided based on the rating of downstream DC/DC converter or other components after the reverse battery protection circuit. A single bi-directional TVS or two back-to-back uni-directional TVS are required to clamp input transients to a safe operating level for the MOSFETs Q1, Q2, and LM74722-Q1.