SLVSDA7E February   2017  – August 2019 TPS61178

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 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 Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Under-voltage Lockout
      2. 8.3.2  Enable and Disable
      3. 8.3.3  Startup
      4. 8.3.4  Load Disconnect Gate Driver
      5. 8.3.5  Adjustable Peak Current Limit
      6. 8.3.6  Output Short Protection (with load disconnected FET)
      7. 8.3.7  Adjustable Switching Frequency
      8. 8.3.8  External Clock Synchronization (TPS611781)
      9. 8.3.9  Error Amplifier
      10. 8.3.10 Slope Compensation
      11. 8.3.11 Start-up with the Output Pre-Biased
      12. 8.3.12 Bootstrap Voltage (BST)
      13. 8.3.13 Over-voltage Protection
      14. 8.3.14 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Operation
      2. 8.4.2 Auto PFM Mode (TPS61178)
      3. 8.4.3 Forced PWM Mode (TPS611781)
  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 Custom Design With WEBENCH® Tools
        2. 9.2.2.2 Setting the Switching Frequency
      3. 9.2.3 Setting the Current Limit
      4. 9.2.4 Setting the Output Voltage
        1. 9.2.4.1 Selecting the Inductor
        2. 9.2.4.2 Selecting the Output Capacitors
        3. 9.2.4.3 Selecting the Input Capacitors
        4. 9.2.4.4 Loop Stability and Compensation
          1. 9.2.4.4.1 Small Signal Model
          2. 9.2.4.4.2 Loop Compensation Design Steps
          3. 9.2.4.4.3 Selecting the Disconnect FET
          4. 9.2.4.4.4 Selecting the Bootstrap Capacitor
          5. 9.2.4.4.5 VCC Capacitor
      5. 9.2.5 TPS61178 Application Waveform
    3. 9.3 System Examples
      1. 9.3.1 TPS61178 with 14-V Output from 2.7-V to 4.4-V Input Voltage
      2. 9.3.2 TPS61178 Without Load Disconnect Function
      3. 9.3.3 TPS611781 External Clock Synchronization
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
      2. 12.1.2 Development Support
        1. 12.1.2.1 Custom Design With WEBENCH® Tools
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Related Links
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Community Resources
    6. 12.6 Trademarks
    7. 12.7 Electrostatic Discharge Caution
    8. 12.8 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.4.3 Forced PWM Mode (TPS611781)

In the Forced PWM mode, the TPS611781 keeps the switching frequency being constant for the whole load range. When the load current decreases, the output of the internal error amplifier decreases as well to lower the inductor peak current and delivers less power from input to output. The high-side FET is not turned off even if the current through the FET goes negative to keep the switching frequency being the same as that of the heavy load.