SLVSCD3C december   2013  – may 2023 TPS65261 , TPS65261-1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 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
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Adjusting the Output Voltage
      2. 7.3.2  Power Failure Detector
      3. 7.3.3  Enable and Adjusting Undervoltage Lockout
      4. 7.3.4  Soft-Start Time
      5. 7.3.5  Power Up Sequencing
        1. 7.3.5.1 External Power Sequencing
        2. 7.3.5.2 Automatic Power Sequencing
      6. 7.3.6  V7V Low Dropout Regulator and Bootstrap
      7. 7.3.7  Out-of-Phase Operation
      8. 7.3.8  Output Overvoltage Protection (OVP)
      9. 7.3.9  Slope Compensation
      10. 7.3.10 Overcurrent Protection
        1. 7.3.10.1 High-side MOSFET Overcurrent Protection
        2. 7.3.10.2 Low-side MOSFET Overcurrent Protection
      11. 7.3.11 Power Good
      12. 7.3.12 Adjustable Switching Frequency
      13. 7.3.13 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Pulse Skipping MODE (PSM)
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Output Inductor Selection
        2. 8.2.2.2 Output Capacitor Selection
        3. 8.2.2.3 Input Capacitor Selection
        4. 8.2.2.4 Loop Compensation
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Parts
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2.4 Loop Compensation

The TPS65261, TPS65261-1 incorporates a peak current mode control scheme. The error amplifier is a trans-conductance amplifier with a gain of 300 µS. A typical type II compensation circuit adequately delivers a phase margin between 60° and 90°. Cb adds a high frequency pole to attenuate high frequency noise when needed. To calculate the external compensation components, follow these steps.

  1. Select switching frequency fsw that is appropriate for application depending on L and C sizes, output ripple, and EMI. Switching frequency between 500kHz to 1MHz gives best trade-off between performance and cost. To optimize efficiency, lower switching frequency is desired.
  2. Set up cross over frequency, ƒc, which is typically between 1/5 and 1/20 of fsw.
  3. RC can be determined by
    Equation 22. GUID-4F05D183-9E6C-4AE5-A7F0-723982D5ED9E-low.gif

    Where Gm_EA is the error amplifier gain (300µS), Gm_PS is the power stage voltage to current conversion gain (7.4A/V).

  4. Calculate CC by placing a compensation zero at or before the dominant pole GUID-6DDEC38F-573A-4250-A025-C2F773379E2F-low.gif
    Equation 23. GUID-7DD75F97-A3F0-415F-892D-A52D680C30BE-low.gif
  5. Optional Cb can be used to cancel the zero from the ESR associated with CO.
    Equation 24. GUID-F1285BA5-D765-437D-AD0D-7273DC30ACA1-low.gif
GUID-20230504-SS0I-HDCS-8V9H-PSDPBSTTQ8VG-low.svg Figure 8-2 DC/DC Loop Compensation