JAJSBM7C September   2011  – October 2017 TPS54623

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     効率と負荷電流との関係
  4. 4 改訂履歴
  5. 5 Pin Configuration and Functions
    1.     Pin 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  VIN and Power VIN Pins (VIN and PVIN)
      2. 7.3.2  Voltage Reference
      3. 7.3.3  Adjusting the Output Voltage
      4. 7.3.4  Safe Start-up into Pre-Biased Outputs
      5. 7.3.5  Error Amplifier
      6. 7.3.6  Slope Compensation
      7. 7.3.7  Enable and Adjusting Undervoltage Lockout
      8. 7.3.8  Slow Start (SS/TR)
      9. 7.3.9  Power Good (PWRGD)
      10. 7.3.10 Bootstrap Voltage (BOOT) and Low Dropout Operation
      11. 7.3.11 Sequencing (SS/TR)
      12. 7.3.12 Output Overvoltage Protection (OVP)
      13. 7.3.13 Overcurrent Protection
        1. 7.3.13.1 High-side MOSFET Overcurrent Protection
        2. 7.3.13.2 Low-side MOSFET Overcurrent Protection
      14. 7.3.14 Thermal Shutdown
      15. 7.3.15 Small Signal Model for Loop Response
      16. 7.3.16 Simple Small Signal Model for Peak Current Mode Control
      17. 7.3.17 Small Signal Model for Frequency Compensation
    4. 7.4 Device Functional Modes
      1. 7.4.1 Fixed Frequency PWM Control
      2. 7.4.2 Continuous Current Mode Operation (CCM)
      3. 7.4.3 Light Load Efficiency Operation
      4. 7.4.4 Adjustable Switching Frequency and Synchronization (RT/CLK)
        1. 7.4.4.1 Adjustable Switching Frequency (RT Mode)
        2. 7.4.4.2 Synchronization (CLK mode)
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Fast Transient Considerations
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        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  Under Voltage Lockout Set Point
        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
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Estimated Circuit Area
    2. 10.2 Layout Examples
  11. 11デバイスおよびドキュメントのサポート
    1. 11.1 デバイス・サポート
      1. 11.1.1 デベロッパー・ネットワークの製品に関する免責事項
      2. 11.1.2 開発サポート
      3. 11.1.3 WEBENCH®ツールによるカスタム設計
    2. 11.2 ドキュメントのサポート
      1. 11.2.1 関連資料
    3. 11.3 ドキュメントの更新通知を受け取る方法
    4. 11.4 コミュニティ・リソース
    5. 11.5 商標
    6. 11.6 静電気放電に関する注意事項
    7. 11.7 Glossary
  12. 12メカニカル、パッケージ、および注文情報

7.3.10 Bootstrap Voltage (BOOT) and Low Dropout Operation

The device has an integrated boot regulator, and requires a small ceramic capacitor between the BOOT and PH pins to provide the gate drive voltage for the high-side MOSFET. The boot capacitor is charged when the BOOT pin voltage is less than VIN and BOOT-PH voltage is below regulation. The value of this ceramic capacitor should be 0.1 μF. A ceramic capacitor with an X7R or X5R grade dielectric with a voltage rating of 10 V or higher is recommended because of the stable characteristics over temperature and voltage.

To improve drop out, the device is designed to operate at 100% duty cycle as long as the BOOT to PH pin voltage is greater than the BOOT-PH UVLO threshold which is typically 2.1 V. When the voltage between BOOT and PH drops below the BOOT-PH UVLO threshold the high-side MOSFET is turned off and the low-side MOSFET is turned on allowing the boot capacitor to be recharged. In applications with split input voltage rails 100% duty cycle operation can be achieved as long as (VIN – PVIN) > 4 V.