SLVSFL4 June   2020 TPS2124

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Input Settling Time and Output Soft Start Control (SS)
        1. 8.3.1.1 Slew Rate vs. CSS Capacitor
      2. 8.3.2 Active Current Limiting (ILM)
      3. 8.3.3 Short-Circuit Protection
      4. 8.3.4 Thermal Protection (TSD)
      5. 8.3.5 Over-voltage Protection (OVx)
      6. 8.3.6 Fast Reverse Current Blocking (RCB)
      7. 8.3.7 Input Voltage Comparator (VCOMP)
    4. 8.4 TPS2124 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Manual Switchover Schematic
      2. 9.2.2 Design Requirements
      3. 9.2.3 Detailed Design Description
      4. 9.2.4 Design Procedure
        1. 9.2.4.1 Selecting OVx Resistors
        2. 9.2.4.2 Selecting Soft-Start Capacitor and Current Limit Resistors
      5. 9.2.5 Application Curves
    3. 9.3 Highest Voltage Operation (VCOMP)
      1. 9.3.1 Application Schematic
      2. 9.3.2 Design Requirements
      3. 9.3.3 Detailed Design Description
      4. 9.3.4 Detailed Design Procedure
      5. 9.3.5 Application Curves
    4. 9.4 Reverse Polarity Protection with TPS2124
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Support Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.3.1 Input Settling Time and Output Soft Start Control (SS)

The TPS2124 will automatically select the first source to become valid (INx >UV and INx <OV). The external capacitor (CSS) will then be used as a timer to wait for the input to finish setting (tSETx). When the settling timer has expired, CSS will continue to charge and set the output slew rate (SRON) for a soft start. After the total turn on time (tONx), soft start will not be used again for INx until it ceases to be valid (INx <UV or INx >OV).

When the second source becomes valid (INy >UV and INy <OV), the external capacitor (CSS) will be used again for a second settling time (tSETy). After tSETy, the TPS2124 will decide whether to continue sourcing the first source, or switchover to the second source. If the second source is selected at the end of tSETy, then CSS will be reused to set the output slew rate (SRON) for a second soft start. After the total turn on time (tONy), soft start will not be used again for INy until it ceases to be valid (INy <UV or INy >OV).

TPS2124 Settling and SS timing.jpgFigure 8. Settling and Soft Start Timing

If INy becomes valid before the end of tONx, tSETy will be delayed and start after tONx has ended.

If INy is not selected during tSETy, a second soft start will not take place, skipping tONy, and CSS will be retired until one of the inputs ceases to be valid.