SLVSB07A July   2011  – March 2018 TPS61256A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Smallest Solution Size Application
      2.      Efficiency vs. Load Current
  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 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 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Softstart
    3. 8.3 Undervoltage Lockout
    4. 8.4 Thermal Regulation
    5. 8.5 Thermal Shutdown
    6. 8.6 Functional Block Diagram
    7. 8.7 Feature Description
      1. 8.7.1 Power-Save Mode
      2. 8.7.2 Current Limit Operation
      3. 8.7.3 Enable
      4. 8.7.4 Load Disconnect And Reverse Current Protection
    8. 8.8 Device Functional Modes
      1. 8.8.1 Load Disconnect And Reverse Current Protection
      2. 8.8.2 Softstart
      3. 8.8.3 Undervoltage Lockout
      4. 8.8.4 Thermal Regulation
      5. 8.8.5 Thermal Shutdown
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Inductor Selection
          1. 9.2.2.1.1 High-frequency Converter Applications
        2. 9.2.2.2 Output Capacitor
        3. 9.2.2.3 Input Capacitor
        4. 9.2.2.4 Checking Loop Stability
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Thermal Information
  12. 12Package Summary
    1. 12.1 Package Dimensions
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 Community Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

8.8.2 Softstart

The TPS61256A device has an internal softstart circuit that limits the inrush current during start-up. The first step in the start-up cycle is the pre-charge phase. During pre-charge, the rectifying switch is turned on until the output capacitor is charged to a value close to the input voltage. The rectifying switch is current limited (approx. 200mA) during this phase. This mechanism is used to limit the output current under short-circuit condition.

Once the output capacitor has been biased to the input voltage, the converter starts switching. The soft-start system progressively increases the on-time as a function of the input-to-output voltage ratio. As soon as the output voltage is reached, the regulation loop takes control and full current operation is permitted.