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

7.4.1 Pulse Skipping MODE (PSM)

The TPS65261 can enter high efficiency pulse skipping mode (PSM) operation at light load current.

When a controller is enabled for PSM operation, the peak inductor current is sensed and compared with 230mA current typically. Because the integrated current comparator catches the peak inductor current only, the average load current entering PSM varies with applications and external output filters. In PSM, the sensed peak inductor current is clamped at 230mA.

When a controller operates in PSM, the inductor current is not allowed to reverse. The reverse current comparator turns off the low-side MOSFET when the inductor current reaches zero, preventing it from reversing and going negative.

Due to the delay in the circuit and current comparator tdly (typical 50ns at VIN = 12V), the real peak inductor current threshold to turn off high-side power MOSFET, can shift higher depending on inductor inductance and input/output voltages. The threshold of peak inductor current to turn off high-side power MOSFET can be calculated by Equation 11.

Equation 11. GUID-4CA15C96-0F06-4004-9C93-847716B57547-low.gif

After the charge accumulated on the Vout capacitor is more than loading need, COMP pin voltage drops to low voltage driven by the error amplifier. There is an internal comparator at the COMP pin. If COMP voltage is lower than 0.35V, the power stage stops switching to save power.

GUID-37D74FF8-6AC3-44F1-A412-E236F7C6F236-low.gifFigure 7-13 PSM Current Comparator