ZHCSO18A december   2022  – june 2023 TPS281C30

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Revision History
  6. 5 Device Comparison Table
  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 Thermal Information
    6. 7.6 Electrical Characteristics
    7. 7.7 SNS Timing Characteristics
    8. 7.8 Switching Characteristics
    9. 7.9 Typical Characteristics
  9. 8 Parameter Measurement Information
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Device Functional Modes
      1. 9.3.1 Working Mode
    4. 9.4 Feature Description
      1. 9.4.1 Accurate Current Sense
        1. 9.4.1.1 High Accuracy Sense Mode
      2. 9.4.2 Programmable Current Limit
        1. 9.4.2.1 Short-Circuit and Overload Protection
        2. 9.4.2.2 Capacitive Charging
      3. 9.4.3 Inductive-Load Switching-Off Clamp
      4. 9.4.4 Inductive Load Demagnetization
      5. 9.4.5 Full Protections and Diagnostics
        1. 9.4.5.1 Open-Load Detection
        2. 9.4.5.2 Thermal Protection Behavior
        3. 9.4.5.3 Undervoltage Lockout (UVLO) Protection
        4. 9.4.5.4 Overvoltage (OVP) Protection
        5. 9.4.5.5 Reverse Polarity Protection
        6. 9.4.5.6 Protection for MCU I/Os
        7. 9.4.5.7 Diagnostic Enable Function
        8. 9.4.5.8 Loss of Ground
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
        1. 10.2.1.1 IEC 61000-4-5 Surge
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Selecting RILIM
        2. 10.2.2.2 Selecting RSNS
    3. 10.3 Power Supply Recommendations
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
        1. 10.4.1.1 EMC Considerations
      2. 10.4.2 Layout Example
        1. 10.4.2.1 PWP Layout without a GND Network
        2. 10.4.2.2 PWP Layout with a GND Network
        3. 10.4.2.3 RGW Layout with a GND Network
      3. 10.4.3 Thermal Considerations
  12. 11Device and Documentation Support
    1. 11.1 接收文档更新通知
    2. 11.2 支持资源
    3. 11.3 Trademarks
    4. 11.4 静电放电警告
    5. 11.5 术语表
  13. 12Mechanical, Packaging, and Orderable Information

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9.4.5.5 Reverse Polarity Protection

Method 1: Blocking diode connected with VBB. Both the device and load are protected when in reverse polarity. The blocking diode does not allow any of the current to flow during reverse battery condition.

GUID-20210603-CA0I-ZVFC-BZXH-SPP0L7D3K0TQ-low.svgFigure 9-17 Reverse Protection With Blocking Diode

Method 2 (GND network protection): Only the high-side device is protected under this connection. The load reverse loop is limited by the load itself. Note when reverse polarity happens, the continuous reverse current through the power FET should be less than Irev. Of the three types of ground pin networks, TI strongly recommends type 3 (the resistor and diode in parallel). No matter what types of connection are between the device GND and the board GND, if a GND voltage shift happens, ensure the following proper connections for the normal operation:

  • Leave the NC pin floating or connect to the device GND. TI recommends to leave floating.
  • Connect the current limit programmable resistor to the device GND.
GUID-20210930-SS0I-GJCJ-QPDV-VK5JSJ8MWHBT-low.svgFigure 9-18 Reverse Protection With GND Network
  • Type 1 (resistor): The higher resistor value contributes to a better current limit effect when the reverse battery or negative ISO pulses. However, it leads to higher GND shift during normal operation mode. Also, consider the resistor’s power dissipation.
    Equation 9. GUID-DC6EA83E-F51D-405F-A244-B7735F0BA529-low.gif
    Equation 10. GUID-9E8AD5B3-41F5-4C7C-8597-081A7FCB96ED-low.gif

    where

    • VGNDshift is the maximum value for the GND shift, determined by the HSS and microcontroller. TI suggests a value ≤ 0.6 V.
    • Inom is the nominal operating current.
    • –VCC is the maximum reverse voltage seen on the battery line.
    • –IGND is the maximum reverse current the ground pin can withstand, which is available in the Absolute Maximum Ratings.

    If multiple high-side power switches are used, the resistor can be shared among devices.

  • Type 2 (diode): A diode is needed to block the reverse voltage, which also brings a ground shift (≈ 600 mV). However, an inductive load is not acceptable to avoid an abnormal status when switching off.
  • Type 3 (resistor and diode in parallel (recommended)): A peak negative spike may occur when the inductive load is switching off, which may damage the HSD or the diode. So, TI recommends a resistor in parallel with the diode when driving an inductive load. The recommended selection are 1-kΩ resistor in parallel with an IF > 100-mA diode. If multiple high-side switches are used, the resistor and diode can be shared among devices.