ZHCSSS7 august   2023 TPS552872-Q1

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 描述
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 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 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  VCC Power Supply
      2. 7.3.2  EXTVCC Power Supply
      3. 7.3.3  Input Undervoltage Lockout
      4. 7.3.4  Enable and Programmable UVLO
      5. 7.3.5  Soft Start
      6. 7.3.6  Shutdown
      7. 7.3.7  Switching Frequency
      8. 7.3.8  Switching Frequency Dithering
      9. 7.3.9  Inductor Current Limit
      10. 7.3.10 Internal Charge Path
      11. 7.3.11 Output Voltage Setting
      12. 7.3.12 Output Current Monitoring and Cable Voltage Droop Compensation
      13. 7.3.13 Output Current Limit
      14. 7.3.14 Overvoltage Protection
      15. 7.3.15 Output Short Circuit Protection
      16. 7.3.16 Power Good
      17. 7.3.17 Constant Current Output Indication
      18. 7.3.18 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Mode
      2. 7.4.2 Power Save Mode
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Switching Frequency
        2. 8.2.2.2 Output Voltage Setting
        3. 8.2.2.3 Inductor Selection
        4. 8.2.2.4 Input Capacitor
        5. 8.2.2.5 Output Capacitor
        6. 8.2.2.6 Output Current Limit
        7. 8.2.2.7 Loop Stability
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 第三方产品免责声明
    2. 9.2 接收文档更新通知
    3. 9.3 支持资源
    4. 9.4 Trademarks
    5. 9.5 静电放电警告
    6. 9.6 术语表
  11. 10Mechanical, Packaging, and Orderable Information

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7.3.12 Output Current Monitoring and Cable Voltage Droop Compensation

The TPS552872-Q1 outputs a voltage at the CDC pin proportional to the sensed voltage across a output current sensing resistor between the ISP pin and the ISN pin. Equation 6 shows the exact voltage at the CDC pin related to the sensed output current.

Equation 6. GUID-5D99AAD8-1B58-43D9-B238-3DBD6B5A6038-low.gif

To compensate the voltage droop across a cable from the output of the USB port to its powered device, the TPS552872-Q1 can lift its output voltage in proportion to the load current by placing a resistor between the CDC pin and AGND pin.

The output voltage rises in proportion to the current sourcing from the CDC pin through the resistor at the CDC pin. It is recommended to use 100-kΩ resistance for the up resistor of the feedback resistor divider. Equation 7 shows the output voltage rise related to the sensed output current, the resistance at the CDC pin, and the up resistor of the output voltage feedback resistor divider.

Equation 7. GUID-893E67E1-0CC1-4231-8ACB-30E3EA37740C-low.gif

where

  • RFB_UP is the up resistor of the resistor divider between the output and the FB pin
  • RCDC is the resistor at the CDC pin

When RFB_UP is 100 kΩ, the output voltage rise versus the sensed output current and the resistor at the CDC pin is shown in Figure 7-6.

GUID-5DAB64E7-C7FC-4350-8FED-09036ABFEB56-low.gifFigure 7-6 Output Voltage Rise versus Output Current