JAJSQB9 January   2024 TPS56A37

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  The Adaptive On-Time Control and PWM Operation
      2. 6.3.2  Power Up Sequence
      3. 6.3.3  Eco-mode Control Scheme
      4. 6.3.4  Soft Start and Prebiased Soft Start
      5. 6.3.5  Enable and Adjusting Undervoltage Lockout
      6. 6.3.6  Output Overcurrent Limit and Undervoltage Protection
      7. 6.3.7  Overvoltage Protection
      8. 6.3.8  UVLO Protection
      9. 6.3.9  Thermal Shutdown
      10. 6.3.10 Output Voltage Discharge
      11. 6.3.11 Power Good
      12. 6.3.12 Large Duty Operation
    4. 6.4 Device Functional Modes
      1. 6.4.1 Standby Operation
      2. 6.4.2 Light Load Operation
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Output Voltage Resistors Selection
        2. 7.2.2.2 Output Filter Selection
        3. 7.2.2.3 Input Capacitor Selection
        4. 7.2.2.4 Bootstrap Capacitor Selection
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 ドキュメントの更新通知を受け取る方法
    3. 8.3 サポート・リソース
    4. 8.4 Trademarks
    5. 8.5 静電気放電に関する注意事項
    6. 8.6 用語集
  10. 9 Revision History
  11. 10Mechanical, 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

6.3.4 Soft Start and Prebiased Soft Start

The TPS56A37 has an adjustable soft-start time that can be set by connecting a capacitor between SS and AGND. Leaving the SS pin floating is set to default internal soft start time 1.8ms. When the EN pin becomes high, the soft-start charge current (ISS) begins charging the external capacitor (CSS) connected between SS and AGND. The device tracks the lower of the internal soft-start voltage or the external soft-start voltage as the reference. The equation for the soft-start time (TSS) is shown in Equation 2.

Equation 2. Tss=Css × VREF Iss

If the external capacitor (CSS) has pre-stored voltage at start-up, the device initially discharge the external capacitor voltage to lower voltage then charge again to prevent inrush start-up.

If the output capacitor is prebiased at start-up, the device initiates switching and starts ramping up only after the internal reference voltage becomes greater than the feedback voltage VFB. This scheme makes sure that the converters ramp up smoothly into regulation point.