ZHCSOF9B april   2022  – june 2023 TPS25981

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 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Switching Characteristics
      1.      16
    8. 7.8 Typical Characteristics
  9. 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 and UVP)
      2. 8.3.2 Overvoltage Lockout (OVLO)
      3. 8.3.3 Inrush Current, Overcurrent, and Short-Circuit Protection
        1. 8.3.3.1 Slew Rate (dVdt) and Inrush Current Control
        2. 8.3.3.2 Circuit-Breaker During Steady-State
        3. 8.3.3.3 Active Current Limiting During Start-Up
        4. 8.3.3.4 Short-Circuit Protection
      4. 8.3.4 Analog Load Current Monitor
      5. 8.3.5 Overtemperature Protection (OTP)
      6. 8.3.6 Fault Response and Indication (FLT)
      7. 8.3.7 Power Good Indication (PG)
      8. 8.3.8 Quick Output Discharge (QOD)
      9. 8.3.9 Reverse Current Blocking FET Driver
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Single Device, Self-Controlled
      2. 9.1.2 Parallel Operation
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Device Selection
        2. 9.2.2.2 Setting Output Voltage Rise Time (tR)
        3. 9.2.2.3 Setting Overcurrent Threshold (ILIM)
        4. 9.2.2.4 Setting Overcurrent Blanking Interval (tITIMER)
        5. 9.2.2.5 Voltage Drop
      3. 9.2.3 Application Curves
  11. 10Power Supply Recommendations
    1. 10.1 Transient Protection
    2. 10.2 Output Short-Circuit Measurements
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 接收文档更新通知
    3. 12.3 支持资源
    4. 12.4 Trademarks
    5. 12.5 静电放电警告
    6. 12.6 术语表
  14. 13Mechanical, Packaging, and Orderable Information

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8.3.3.1 Slew Rate (dVdt) and Inrush Current Control

During hot-plug events or while trying to charge a large output capacitance at start-up, there can be a large inrush current. If the inrush current is not managed properly, it can damage the input connectors and cause the system power supply to droop leading to unexpected restarts elsewhere in the system. The inrush current during turn-on is directly proportional to the load capacitance and rising slew rate. Equation 3 can be used to find the slew rate (SR) required to limit the inrush current (IINRUSH) for a given load capacitance (COUT):

Equation 3. S R   V m s = I I N R U S H   ( m A ) C O U T   µ F

A capacitor can be connected to the dVdt pin to control the rising slew rate and lower the inrush current during turn on. Use Equation 4 to calculate the required CdVdt capacitance to produce a given slew rate.

Equation 4. CdVdt pF=3300SR Vms

The fastest output slew rate is achieved by leaving the dVdt pin open.

Note:

For CdVdt > 10 nF, TI recommends to add a 100-Ω resistor in series with the capacitor on the dVdt pin.