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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9.4.5.1 Open-Load Detection

On-State Open Load Detection

When the main channel is enabled faults are diagnosed by reading the voltage on the SNS or FLT pin and judged by the user. A benefit of high-accuracy current sense is that this device can achieve a very low open-load detection threshold, which correspondingly expands the normal operation region. As explained in section high accuracy sense mode, this mode can be used to sense 6mA currents accurately.

Off-State Open Load Detection

In the off state, if a load is connected, the output voltage is pulled to 0V. In the case of an open load, the output voltage is close to the supply voltage, VS – VOUT < Vol,off. The FLT pin goes low to indicate the fault to the MCU, and the SNS pin is pulled up to ISNSFH. There is always a leakage current Iol,off present on the output, due to the internal logic control path or external humidity, corrosion, and so forth. Thus, TI implimented an internal pullup resistor to offset the leakage current. This pullup current should be less than the output load current to avoid false detection in the normal operation mode. To reduce the standby current, TI implimented a switch in series with the pullup resistor controlled by the DIAG_EN pin. The pull up resistor value is 150 kΩ.

GUID-20210930-SS0I-BG22-SWGN-DB2XHV9XSFLN-low.svgFigure 9-15 Off-State Open-Load Detection Circuit