SLVSA94K December   2012  – May 2019 TPS50301-HT

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Efficiency vs Load Current, VIN = 5 V
  4. 4 Revision History
  5. 5 Description (continued)
  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 Dissipation Ratings
    7. 7.7 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  VIN and Power VIN Pins (VIN and PVIN)
      2. 8.3.2  PVIN vs Frequency
      3. 8.3.3  Voltage Reference
      4. 8.3.4  Adjusting the Output Voltage
      5. 8.3.5  Maximum Duty Cycle Limit
      6. 8.3.6  PVIN vs Frequency
      7. 8.3.7  Safe Start-Up into Prebiased Outputs
      8. 8.3.8  Error Amplifier
      9. 8.3.9  Slope Compensation
      10. 8.3.10 Enable and Adjust UVLO
      11. 8.3.11 Adjustable Switching Frequency and Synchronization (SYNC)
      12. 8.3.12 Slow Start (SS/TR)
      13. 8.3.13 Power Good (PWRGD)
      14. 8.3.14 Bootstrap Voltage (BOOT) and Low Dropout Operation
      15. 8.3.15 Sequencing (SS/TR)
      16. 8.3.16 Output Overvoltage Protection (OVP)
      17. 8.3.17 Overcurrent Protection
        1. 8.3.17.1 High-Side MOSFET Overcurrent Protection
        2. 8.3.17.2 Low-Side MOSFET Overcurrent Protection
      18. 8.3.18 TPS50301-HT Thermal Shutdown
      19. 8.3.19 Turn-On Behavior
      20. 8.3.20 Small Signal Model for Loop Response
      21. 8.3.21 Simple Small Signal Model for Peak Current Mode Control
      22. 8.3.22 Small Signal Model for Frequency Compensation
    4. 8.4 Device Functional Modes
      1. 8.4.1 Fixed-Frequency PWM Control
      2. 8.4.2 Continuous Current Mode (CCM) Operation
  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  Operating Frequency
        3. 9.2.2.3  Output Inductor Selection
        4. 9.2.2.4  Output Capacitor Selection
        5. 9.2.2.5  Input Capacitor Selection
        6. 9.2.2.6  Slow Start Capacitor Selection
        7. 9.2.2.7  Bootstrap Capacitor Selection
        8. 9.2.2.8  Undervoltage Lockout (UVLO) Set Point
        9. 9.2.2.9  Output Voltage Feedback Resistor Selection
          1. 9.2.2.9.1 Minimum Output Voltage
        10. 9.2.2.10 Compensation Component Selection
      3. 9.2.3 Parallel Operation
      4. 9.2.4 Application Curve
  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 Development Support
        1. 12.1.1.1 Custom Design With WEBENCH® Tools
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information
    1. 13.1 Device Nomenclature

Package Options

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

8.3.20 Small Signal Model for Loop Response

Figure 25 shows an equivalent model for the device control loop, which can be modeled in a circuit simulation program to check frequency response and transient responses. The error amplifier is a transconductance amplifier with a gm of 1300 μA/V. The error amplifier can be modeled using an ideal voltage-controlled current source. The resistor, Roea (30 MΩ), and capacitor, Coea (20.7 pF), model the open-loop gain and frequency response of the error amplifier. The 1-mV ac voltage source between the nodes a and b effectively breaks the control loop for the frequency response measurements. Plotting a/c and c/b show the small signal responses of the power stage and frequency compensation respectively. Plotting a/b shows the small signal response of the overall loop. The dynamic loop response can be checked by replacing the RL with a current source with the appropriate load-step amplitude and step rate in a time domain analysis.

TPS50301-HT loop_resp1_lvsa94.gifFigure 25. Small Signal Model For Loop Response