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

8.3.22 Small Signal Model for Frequency Compensation

The device uses a transconductance amplifier for the error amplifier and readily supports two of the commonly used frequency compensation circuits shown in Figure 28. In Type 2A, one additional high-frequency pole is added to attenuate high-frequency noise.

The following design guidelines are provided for advanced users who prefer to compensate using the general method. The step-by-step design procedure described in Detailed Design Procedure may also be used.

TPS50301-HT f_compen_lvsa94.gifFigure 28. Types of Frequency Compensation

The general design guidelines for device loop compensation are as follows:

  1. Determine the crossover frequency ƒc. A good starting point is one-tenth of the switching frequency, ƒSW.
  2. R3 can be determined by:
    3. Equation 17. TPS50301-HT eq12_r3_lvs949.gif

    where

    • gmea is the GM amplifier gain ( 1300 μA/V).
    • gmps is the power stage gain (18 A/V).
    • Vref is the reference voltage (0.795 V)
  3. Place a compensation zero at the dominant pole TPS50301-HT inline1_lvs949.gif.
    C1 can be determined by
    4. Equation 18. TPS50301-HT eq13_c1_lvs949.gif
  4. C2 is optional. It can be used to cancel the zero from the equivalent series resistance (ESR) of the output capacitor Co.
    5. Equation 19. TPS50301-HT eq14_c2_lvs949.gif

NOTE

For PSpice models and WEBENCH design tool, see the Tools & Software tab.

  1. PSpice average model (stability – bode plot)
  2. PSpice transient model (switching waveforms)
  3. WEBENCH design tool www.ti.com/product/TPS50301-HT/toolssoftware