SLVSA99C May   2011  – April 2018 TPS61260 , TPS61261

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
  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 Handling 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
    1. 7.1 Schematic and List of Components
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1 Controller Circuit
      2. 8.3.2 Synchronous Boost Operation
      3. 8.3.3 Power Save Mode
      4. 8.3.4 Device Enable
      5. 8.3.5 Softstart and Short Circuit Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Undervoltage Lockout
      2. 8.4.2 Output Overvoltage Protection
    5. 8.5 Programming
      1. 8.5.1 Programming the Output Voltage
      2. 8.5.2 Programming the Output Current
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 TPS61260 3.3-V Output Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Inductor Selection
          2. 9.2.1.2.2 Capacitor Selection
            1. 9.2.1.2.2.1 Input Capacitor
            2. 9.2.1.2.2.2 Output Capacitor
        3. 9.2.1.3 TPS61260 3.3-V Output Application Performance Plots
      2. 9.2.2 TPS61261 Application as LED Driver
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 TPS61261 Application as LED Driver Performance Plots
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Related Links
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.5 Softstart and Short Circuit Protection

During startup of the converter, duty cycle and peak current are limited in order to avoid high peak currents flowing from the input. After being enabled, the device starts operating. Until the output voltage reaches about 0.4 V, the average output current ramps up from zero to the programmed value, as the output voltage increases. As soon as the output current has reached the programmed value, it stays regulated at that value until the load conditions demand less current. This typically happens when the output capacitor is charged and the output voltage is regulated.

During startup, the device can seamlessly change modes of operation. When the input voltage is higher than the output voltage, the device operates in a linear mode using the rectifying switches for control. If the input voltage is lower than the output voltage it operates in a standard boost conversion mode. Boost conversion is non-synchronous when the output voltage is below approximately 1.8 V and it is synchronous if the output voltage is higher than approximately 1.8 V.

At short circuit conditions at the output, the output current is limited to the programmed average current. If the short at the output causes the output voltage to drop below 0.4 V, the average current decreases approximately linearly with the output voltage down to zero.

The devices can monotonically start into a pre-bias on the output.