ZHCSNR4B May   2021  – April 2022 TPS25946

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 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.      15
    8. 7.8 Typical Characteristics
  8. 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 Active Current Limiting
        3. 8.3.3.3 Short-Circuit Protection
      4. 8.3.4 Analog Load Current Monitor
      5. 8.3.5 Reverse Current Protection
      6. 8.3.6 Overtemperature Protection (OTP)
      7. 8.3.7 Fault Response and Indication (FLT)
      8. 8.3.8 Power Good Indication (PG)
      9. 8.3.9 Input Supply Good Indication (SPLYGD)
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Single Device, Self-Controlled
    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 Overvoltage Threshold
        3. 9.2.2.3 Setting Output Voltage Rise Time (tR)
        4. 9.2.2.4 Setting Power Good Assertion Threshold
        5. 9.2.2.5 Setting Overcurrent Threshold (ILIM)
        6. 9.2.2.6 Setting Overcurrent Blanking Interval (tITIMER)
        7. 9.2.2.7 Selecting External Bias Resistor (R5)
        8. 9.2.2.8 Selecting External Diode (D1)
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
    1. 10.1 Transient Protection
    2. 10.2 Output Short-Circuit Measurements
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 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 Electrostatic Discharge Caution
    6. 12.6 术语表
  13. 13Mechanical, Packaging, and Orderable Information

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8.3.4 Analog Load Current Monitor

The TPS25946xx allows the system to accurately monitor the load current by providing an analog current sense output on the ILM pin which is proportional to the current through the FET from IN to OUT. The user can sense the voltage (VILM) across the RILM to get a measure of the output load current.

Equation 7.

The waveform below shows the ILM signal response to a load step at the output.

GUID-C4D6F9F8-8EB9-44D3-A791-55806A3C0DF0-low.gif
VIN = 12 V, COUT = 22 μF, RILM = 1150 Ω, IOUT varied dynamically between 0 A and 3.5 A
Figure 8-8 Analog Load Current Monitor Response
Note:

  1. The ILM pin is sensitive to capacitive loading. Careful design and layout is needed to ensure the parasitic capacitive loading on the ILM pin is < 50 pF for stable operation.

  2. The ILM pin can only report the current flowing from IN to OUT and not from OUT to IN.