SLVSFN6 December   2020 TPS54622-EP

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configurations and Functions
  6. 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
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Fixed-Frequency PWM Control
      2. 7.3.2  Continuous Current Mode Operation (CCM)
      3. 7.3.3  VIN and Power VIN Pins (VIN and PVIN)
      4. 7.3.4  Voltage Reference
      5. 7.3.5  Adjusting the Output Voltage
      6. 7.3.6  Safe Start-Up Into Prebiased Outputs
      7. 7.3.7  Error Amplifier
      8. 7.3.8  Slope Compensation
      9. 7.3.9  Enable and Adjusting Undervoltage Lockout
      10. 7.3.10 Adjustable Switching Frequency and Synchronization (RT/CLK)
      11. 7.3.11 Slow Start (SS/TR)
      12. 7.3.12 Power Good (PWRGD)
      13. 7.3.13 Output Overvoltage Protection (OVP)
      14. 7.3.14 Overcurrent Protection
        1. 7.3.14.1 High-Side MOSFET Overcurrent Protection
        2. 7.3.14.2 Low-Side MOSFET Overcurrent Protection
      15. 7.3.15 Thermal Shutdown
      16. 7.3.16 Small Signal Model for Loop Response
      17. 7.3.17 Simple Small Signal Model for Peak Current Mode Control
      18. 7.3.18 Small Signal Model for Frequency Compensation
    4. 7.4 Device Functional Modes
      1. 7.4.1 Adjustable Switching Frequency (RT Mode)
      2. 7.4.2 Synchronization (CLK Mode)
      3. 7.4.3 Bootstrap Voltage (BOOT) and Low Dropout Operation
      4. 7.4.4 Sequencing (SS/TR)
  8. 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 Procedures
        1. 8.2.2.1  Custom Design With WEBENCH® Tools
        2. 8.2.2.2  Operating Frequency
        3. 8.2.2.3  Output Inductor Selection
        4. 8.2.2.4  Output Capacitor Selection
        5. 8.2.2.5  Input Capacitor Selection
        6. 8.2.2.6  Slow-Start Capacitor Selection
        7. 8.2.2.7  Bootstrap Capacitor Selection
        8. 8.2.2.8  Undervoltage Lockout Setpoint
        9. 8.2.2.9  Output Voltage Feedback Resistor Selection
          1. 8.2.2.9.1 Minimum Output Voltage
        10. 8.2.2.10 Compensation Component Selection
        11. 8.2.2.11 Fast Transient Considerations
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
    3. 10.3 Estimated Circuit Area
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
      2. 11.1.2 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

7.3.14.2 Low-Side MOSFET Overcurrent Protection

While the low-side MOSFET is turned on its conduction current is monitored by the internal circuitry. During normal operation the low-side MOSFET sources current to the load. At the end of every clock cycle, the low-side MOSFET sourcing current is compared to the internally set low-side sourcing current limit. If the low-side sourcing current is exceeded the high-side MOSFET is not turned on and the low-side MOSFET stays on for the next cycle. The high-side MOSFET is turned on again when the low-side current is below the low-side sourcing current limit at the start of a cycle.

The low-side MOSFET may also sink current from the load. If the low-side sinking current limit is exceeded the low-side MOSFET is turned off immediately for the rest of that clock cycle. In this scenario both MOSFETs are off until the start of the next cycle.

Furthermore, if an output overload condition (as measured by the COMP pin voltage) has lasted for more than the hiccup wait time which is programmed for 512 switching cycles, the device will shut down itself and restart after the hiccup time of 16384 cycles. The hiccup mode helps to reduce the device power dissipation under severe overcurrent conditions.