ZHCSIQ0F August   2018  – August 2020 TPS2120 , TPS2121

PRODUCTION DATA  

  1. 特性
  2. 应用
  3. 说明
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1.     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 Typical Characteristics
  8. Parameter Measurement Information
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Input Settling Time and Output Soft Start Control (SS)
        1. 9.3.1.1 Slew Rate vs. CSS Capacitor
      2. 9.3.2 Active Current Limiting (ILM)
      3. 9.3.3 Short-Circuit Protection
      4. 9.3.4 Thermal Protection (TSD)
      5. 9.3.5 Overvoltage Protection (OVx)
      6. 9.3.6 Fast Reverse Current Blocking (RCB)
      7. 9.3.7 Output Voltage Dip and Fast Switchover Control (TPS2121 only)
      8. 9.3.8 Input Voltage Comparator (VCOMP)
    4. 9.4 TPS2120 Device Functional Modes
    5. 9.5 TPS2121 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Manual Switchover Schematic
      2. 10.2.2 Design Requirements
      3. 10.2.3 Detailed Design Description
      4. 10.2.4 Design Procedure
        1. 10.2.4.1 Selecting PR1 and CP2 Resistors
        2. 10.2.4.2 Selecting OVx Resistors
        3. 10.2.4.3 Selecting Soft-Start Capacitor and Current Limit Resistors
      5. 10.2.5 Application Curves
    3. 10.3 Automatic Switchover with Priority (XCOMP)
      1. 10.3.1 Application Schematic
      2. 10.3.2 Design Requirements
      3. 10.3.3 Detailed Design Description
      4. 10.3.4 Design Procedure
        1. 10.3.4.1 Selecting PR1 and CP2 Resistors
      5. 10.3.5 Application Curves
    4. 10.4 Automatic Seamless Switchover with Priority (XREF)
      1. 10.4.1 Application Schematic
      2. 10.4.2 Design Requirements
      3. 10.4.3 Detailed Design Description
      4. 10.4.4 Application Curves
    5. 10.5 Highest Voltage Operation (VCOMP)
      1. 10.5.1 Application Schematic
      2. 10.5.2 Design Requirements
      3. 10.5.3 Detailed Design Description
      4. 10.5.4 Detailed Design Procedure
      5. 10.5.5 Application Curves
    6. 10.6 Reverse Polarity Protection with TPS212x
    7. 10.7 Hotplugging with TPS212x
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Links
    2. 13.2 接收文档更新通知
    3. 13.3 支持资源
    4. 13.4 Trademarks
    5. 13.5 静电放电警告
    6. 13.6 术语表
  14. 14Mechanical, Packaging, and Orderable Information

Output Voltage Dip and Fast Switchover Control (TPS2121 only)

After input settling and soft start time, the TPS2121 utilizes a fast switchover to minimize output voltage drop. Where VSW is the output voltage when the switchover is triggered and tSW is the time until the output voltage stops dipping. The amount of voltage dip during the switchover time is a function of output load current (IOUT) and load capacitance (COUT). The minimum output voltage during switchover can be found using the following equations:

Equation 3. GUID-B05762A4-605B-47B1-9469-51C94D11E126-low.gif

Where:

Equation 4. GUID-967B5F2F-B1F2-42B4-8F1D-839B9AEA58D7-low.gif
GUID-83E92B2E-8D22-45BE-B882-15CB2281947A-low.jpgFigure 9-7 Minimum Output Voltage During Fast Switchover

If switching from a lower to a higher voltage, the selected channel will not detect reverse voltage and shall turn on immediately using the current monitor to limit the output current to a safe level. If the output current reaches the current limit during fast switchover, this will increase the total time until the output reaches steady state.

GUID-AC9D11A0-5569-4428-830B-6F012BF9D05A-low.gifFigure 9-8 Fast Switchover from Lower to Higher Voltage

If an input is selected while the output voltage is still a higher voltage, that channel will continue to block reverse current by waiting to fast turn on until the output drops below the VRCB threshold.

GUID-1568F100-E2C0-451B-8CEC-9411266CF8EC-low.gifFigure 9-9 Fast Switchover from Higher to Lower Voltage