SLVSGT8 December   2022 TPS25961

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Undervoltage Protection (UVP) and Undervoltage Lockout (UVLO)
      2. 7.3.2 Overvoltage Protection
      3. 7.3.3 Inrush Current, Overcurrent and Short Circuit Protection
        1. 7.3.3.1 Slew Rate and Inrush Current Control (dVdt)
        2. 7.3.3.2 Active Current Limiting
        3. 7.3.3.3 Short-Circuit Protection
      4. 7.3.4 Overtemperature Protection (OTP)
      5. 7.3.5 Fault Response
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Adapter input protection for set-top boxes
      2. 8.2.2 Design Requirements
      3. 8.2.3 Detailed Design Procedure
        1. 8.2.3.1 Programming the Current-Limit Threshold: RILM Selection
        2. 8.2.3.2 Undervoltage and Overvoltage Lockout Set Point
        3. 8.2.3.3 Output Voltage Rise Time (tR)
      4. 8.2.4 Application Curves
    3. 8.3 Application Example
      1. 8.3.1 Application Curves
    4. 8.4 Power Supply Recommendations
      1. 8.4.1 Transient Protection
      2. 8.4.2 Output Short-Circuit Measurements
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  10. 10Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.1 Undervoltage Protection (UVP) and Undervoltage Lockout (UVLO)

TPS25961 constantly monitors the input supply to ensure that the load is powered up only when the voltage is at a sufficient level. During the start-up condition, the device waits for the input supply to rise above an internal fixed threshold VUVP(R) before it proceeds to turn ON the FET. Similarly, during the ON condition, if the input supply falls below the UVP threshold VUVP(F), the FET is turned OFF. The UVP rising and falling thresholds are slightly different, thereby providing some hysteresis and ensuring stable operation around the threshold voltage.

The TPS25961 also provides an user adjustable UVLO mechanism to ensure that the load is powered up only when the voltage is at a sufficient level as per the specific system requirement. This can be achieved by dividing the input supply and feeding it to the EN/UVLO pin. Whenever the voltage at the EN/UVLO pin falls below a threshold VUVLO(F), the device turns OFF the FET. The FET is turned ON again when the voltage rises above the threshold VUVLO(R). The rising and falling thresholds on this pin are slightly different, thereby providing some hysteresis and ensuring stable operation around the threshold voltage.

The user must choose the resistor divider values appropriately to map the desired input undervoltage level to the UVLO threshold of the part.

GUID-20220623-SS0I-7Z8H-C9MD-T6C7QHBZTT5C-low.gif Figure 7-1 Adjustable Undervoltage Lockout
The equation below shows the calculations for the resistor divider values to be used to set the UVLO set-point for a given voltage supply.
Equation 1. VIN(UV)  = VUVLO(F) × R1 + R2R2