ZHCSSS8 august   2023 TPS552872

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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7.3.7 Switching Frequency

The TPS552872 uses a fixed frequency average current control scheme. The switching frequency is between 200 kHz and 2.2 MHz set by placing a resistor at the FSW pin. An internal amplifier holds this pin at a fixed voltage of 1 V. The setting resistance is between maximum of 100 kΩ and minimum of 8.4 kΩ. Use Equation 3 to calculate the resistance by a given switching frequency.

Equation 3. fSW=10000.05×RFSW+35 (MHz)

where

  • RFSW is the resistance at the FSW pin (Ω)

For noise-sensitive applications, the TPS552872 can be synchronized to an external clock signal applied to the DITH/SYNC pin. The duty cycle of the external clock is recommended in the range of 30% to 70%. A resistor also must be connected to the FSW pin when the TPS552872 is switching by the external clock. The external clock frequency at the DITH/SYNC pin must have lower than 0.4-V low level voltage and must be within ±30% of the corresponding frequency set by the resistor. Figure 7-3 is a recommended configuration.

GUID-8AD10F00-5D70-4C59-9AFE-D593616FAED0-low.gifFigure 7-3 External Clock Configuration