SLVSFL4 June   2020 TPS2124

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Typical Application
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin Functions
  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. Parameter Measurement Information
  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. 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

パッケージ・オプション

メカニカル・データ(パッケージ|ピン)
サーマルパッド・メカニカル・データ
発注情報

Detailed Design Description

The TPS2124 device can be configured to manually switch between IN1 and IN2 through an external GPIO. In this example, an external MCU signal is selecting between main power and auxiliary power to power a downstream load. By manually toggling the TPS2124, the device will switch between both sources, even if one supply is higher than the other supply. Ultimately, the main factor that will determine the switchover time between IN1 (5 V) and IN2 (3.3 V) is the output load.

Manual switchover can be enabled by configuring the TPS2124 for internal voltage reference control scheme (VREF). In the VREF scheme, if the voltage on PR1 is higher than the internal VREF voltage, 1.06 V (typical), the device will select IN1 as the output. If the voltage on PR1 drops below VREF, then the device will switch to IN2, as long as IN2 is presenting a valid input voltage. IN1 is commonly connected to PR1 with an external resistor divider. OV1 and OV2 can be configured to provide overvoltage protection. The ST pin can be pulled high with a resistor to provide feedback on the status of the system. If the status pin is high, IN1 is the output. If the pin is low, IN2 is the output. If this feature is not required, the ST pin can be connected to GND.

On the TPS2124, by connecting an external signal to the select pin (SEL), the device can override the PR1/VREF comparison. If the voltage on SEL is higher than VREF at approximately (1.06 V), then the device will select IN2, as shown on Table 2. If the voltage on SEL drops below VREF, then the device will switch to IN1 as long as PR1 >= VREF. Otherwise, the highest voltage input will be chosen between IN1 and IN2. In this example, since the IN1 is higher than IN2, at 5 V, it will be selected.

Figure 14 shows the application schematic for this design example on the TPS2124.

TPS2124 TPS2124_Manual_2.jpgFigure 14. TPS2124 Manual Switchover