JAJSHW4 September   2019 LM74202-Q1

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      概略回路図
      2.      12V での ISO16750-2 ロードダンプ・パルス 5b 性能
  4. 4 改訂履歴
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1      Absolute Maximum Ratings
    2. 6.2      ESD Ratings
    3. 6.3      Recommended Operating Conditions
    4. Table 1. Thermal Information
    5. 6.4      Electrical Characteristics
    6. 6.5      Timing Requirements
    7. 6.6      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 Undervoltage Lockout (UVLO)
      2. 8.3.2 Overvoltage Protection (OVP)
      3. 8.3.3 Reverse Battery Protection
      4. 8.3.4 Hot Plug-In and In-Rush Current Control
      5. 8.3.5 Overload and Short Circuit Protection
        1. 8.3.5.1 Overload Protection
          1. 8.3.5.1.1 Active Current Limiting
          2. 8.3.5.1.2 Electronic Circuit Breaker with Overload Timeout, MODE = OPEN
        2. 8.3.5.2 Short Circuit Protection
          1. 8.3.5.2.1 Start-Up With Short-Circuit On Output
        3. 8.3.5.3 FAULT Response
          1. 8.3.5.3.1 Look Ahead Overload Current Fault Indicator
        4. 8.3.5.4 Current Monitoring
        5. 8.3.5.5 IN, OUT, RTN and GND Pins
        6. 8.3.5.6 Thermal Shutdown
        7. 8.3.5.7 Low Current Shutdown Control (SHDN)
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Step by Step Design Procedure
        2. 9.2.2.2 Setting Undervoltage Lockout and Overvoltage Set Point for Operating Voltage Range
        3. 9.2.2.3 Programming the Current-Limit Threshold—R(ILIM) Selection
        4. 9.2.2.4 Programming Current Monitoring Resistor—RIMON
        5. 9.2.2.5 Limiting the Inrush Current
          1. 9.2.2.5.1 Selection of Input TVS for Transient Protection
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 Transient Protection
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 ドキュメントのサポート
      1. 12.1.1 関連資料
    2. 12.2 ドキュメントの更新通知を受け取る方法
    3. 12.3 コミュニティ・リソース
    4. 12.4 商標
    5. 12.5 静電気放電に関する注意事項
    6. 12.6 Glossary
  13. 13メカニカル、パッケージ、および注文情報

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

8.3.5.2 Short Circuit Protection

During a transient output short circuit event, the current through the device increases very rapidly. As the current-limit amplifier cannot respond quickly to this event due to its limited bandwidth, the device incorporates a fast-trip comparator, with a threshold I(FASTRIP). The fast-trip comparator turns off the internal FET after a duration of tFASTTRIP(dly), when the current through the FET exceeds I(FASTRIP) (I(OUT) > I(FASTRIP)), and terminates the rapid short-circuit peak current. The fast-trip threshold is internally set to 87% higher than the programmed overload current limit (I(FASTRIP) = 1.87 × I(OL) + 0.015). The fast-trip circuit holds the internal FET off for only a few microseconds, after which the device turns back on slowly, allowing the current-limit loop to regulate the output current to I(OL). Then the device behaves similar to overload condition. Figure 33 and Figure 34 illustrate the behavior of the system when the current exceeds the fast-trip threshold.

LM74202-Q1 scope_shot_15_slvsdg2.png
VIN = 24 V, RILIM = 5.36 kΩ
Figure 33. Output Hot Short Functionality at 24-V Input
LM74202-Q1 scope_shot_16_slvsdg2.png
Figure 34. Zoomed at the Instance of Output Short