SLVS413K October   2002  – July 2022 TPS61040 , TPS61041

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 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 Peak Current Control
      2. 7.3.2 Soft Start
      3. 7.3.3 Enable
      4. 7.3.4 Undervoltage Lockout
      5. 7.3.5 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Inductor Selection, Maximum Load Current
        2. 8.2.2.2 Setting the Output Voltage
        3. 8.2.2.3 Line and Load Regulation
        4. 8.2.2.4 Output Capacitor Selection
        5. 8.2.2.5 Input Capacitor Selection
        6. 8.2.2.6 Diode Selection
      3. 8.2.3 Application Curves
    3. 8.3 System Examples
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Third-Party Products Disclaimer
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.3.1 Peak Current Control

The internal switch turns on until the inductor current reaches the typical dc current limit (ILIM) of 400 mA (TPS61040) or 250 mA (TPS61041). Due to the internal propagation delay of typical 100 ns, the actual current exceeds the dc current limit threshold by a small amount. The typical peak current limit can be calculated:

Equation 1. GUID-85EA91BF-7351-49AB-B1DB-E2BE29837DF2-low.gif

The higher the input voltage and the lower the inductor value, the greater the peak.

By selecting the TPS6104x, it is possible to tailor the design to the specific application current limit requirements. A lower current limit supports applications requiring lower output power and allows the use of an inductor with a lower current rating and a smaller form factor. A lower current limit usually has a lower output voltage ripple as well.