SLVS736C February   2008  – October 2023 TPS2550 , TPS2551

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 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
  9. 8 Parameter Measurement Information
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Overcurrent
      2. 9.3.2 Reverse-Voltage Protection
      3. 9.3.3 FAULT Response
      4. 9.3.4 Undervoltage Lockout (UVLO)
      5. 9.3.5 ENABLE ( EN or EN)
      6. 9.3.6 Thermal Sense
      7. 9.3.7 Device Functional Modes
    4. 9.4 Programming
      1. 9.4.1 Programming the Current-Limit Threshold
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Two-Level Current-Limit Circuit
      2. 10.2.2 Design Requirements
      3. 10.2.3 Detail Design Procedures
        1. 10.2.3.1 Designing Above a Minimum Current Limit
        2. 10.2.3.2 Designing Below a Maximum Current Limit
        3. 10.2.3.3 Input and Output Capacitance
      4. 10.2.4 Auto-Retry Functionality
      5. 10.2.5 Latch-Off Functionality
      6. 10.2.6 Typical Application as USB Power Switch
        1. 10.2.6.1 Design Requirements
          1. 10.2.6.1.1 USB Power-Distribution Requirements
        2. 10.2.6.2 Detail Design Procedures
          1. 10.2.6.2.1 Universal Serial Bus (USB) Power-Distribution Requirements
    3. 10.3 Power Supply Recommendations
      1. 10.3.1 Self-Powered and Bus-Powered Hubs
      2. 10.3.2 Low-Power Bus-Powered and High-Power Bus-Powered Functions
      3. 10.3.3 Power Dissipation and Junction Temperature
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.2.3.2 Designing Below a Maximum Current Limit

Some applications require that current-limiting must occur below a certain threshold. For this example, assume that the desired upper current-limit threshold must be below 1.25 A to protect an up-stream power supply. Use the IOC equations and Figure 9-1 to select RILIM.

  • IOC(max) (mA) = 1250 mA
  • IOC(max) (mA) = (24500 V) / (RILIM (kΩ)) 0.975 + 50
  • RILIM (kΩ) = [(24500 V) / (IOC(max) (mA) - 50)]1/0.975
  • RILIM = 22.05 kΩ

Select the closest 1% resistor greater than the calculated value: RILIM = 22 kΩ. This selection sets the maximum current-limit threshold at 1.25 A . Use the IOS equations, Figure 9-1, and the previously calculated value for RILIM to calculate the minimum resulting current-limit threshold.

  • RILIM = 22 kΩ
  • IOS(min) (mA) = (39700 V) / (RILIM (kΩ)) 1.342 + 50
  • IOS(min) (mA) = (39700 V) / (22 (kΩ)) 1.342 + 50
  • IOS(min) = 677 mA

The resulting minimum current-limit threshold is 677 mA with a 22 kΩ resistor.