ZHCSK76 September   2019 LM74202-Q1

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      简化原理图
      2.      12V 条件下的 ISO16750-2 负载突降脉冲 5b 性能
  4. 修订历史记录
  5. Pin Configuration and Functions
    1.     Pin Functions
  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. Parameter Measurement Information
  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. 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器件和文档支持
    1. 12.1 文档支持
      1. 12.1.1 相关文档
    2. 12.2 接收文档更新通知
    3. 12.3 社区资源
    4. 12.4 商标
    5. 12.5 静电放电警告
    6. 12.6 Glossary
  13. 13机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

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