JAJS371D January   2009  – September 2023 TPS54332

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  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 Switching Characteristics
    7. 6.7 Typical Characteristics: Characterization Curves
    8. 6.8 Typical Characteristics: Supplemental Application Curves
  8. 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  Voltage Reference (Vref)
      3. 7.3.3  Bootstrap Voltage (BOOT)
      4. 7.3.4  Enable and Adjustable Input Undervoltage Lockout (VIN UVLO)
      5. 7.3.5  Programmable Slow Start Using the SS Pin
      6. 7.3.6  Error Amplifier
      7. 7.3.7  Slope Compensation
      8. 7.3.8  Current Mode Compensation Design
      9. 7.3.9  Overcurrent Protection and Frequency Shift
      10. 7.3.10 Overvoltage Transient Protection
      11. 7.3.11 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation With VIN < 3.5 V
      2. 7.4.2 Operation With EN Control
      3. 7.4.3 Eco-mode
  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  Custom Design with WEBENCH® Tools
        2. 8.2.2.2  Switching Frequency
        3. 8.2.2.3  Output Voltage Set Point
        4. 8.2.2.4  Input Capacitors
        5. 8.2.2.5  Output Filter Components
        6. 8.2.2.6  Inductor Selection
        7. 8.2.2.7  Capacitor Selection
        8. 8.2.2.8  Compensation Components
        9. 8.2.2.9  Bootstrap Capacitor
        10. 8.2.2.10 Catch Diode
        11. 8.2.2.11 Output Voltage Limitations
        12. 8.2.2.12 Power Dissipation Estimate
      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
      3. 8.4.3 Estimated Circuit Area
      4. 8.4.4 Electromagnetic Interference (EMI) Considerations
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 Custom Design with WEBENCH® Tools
    2. 9.2 サポート・リソース
    3. 9.3 ドキュメントの更新通知を受け取る方法
    4. 9.4 Trademarks
    5. 9.5 静電気放電に関する注意事項
    6. 9.6 用語集
  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

7.3.5 Programmable Slow Start Using the SS Pin

TI highly recommends programing the slow-start time externally because no slow-start time is implemented internally. The TPS54332 effectively uses the lower voltage of the internal voltage reference or the SS pin voltage as the power supply reference voltage fed into the error amplifier and regulates the output accordingly. A capacitor (CSS) on the SS pin-to-ground implements a slow-start time. The TPS54332 has an internal pullup current source of 2 μA that charges the external slow-start capacitor. The equation for the slow-start time (10% to 90%) is shown in Equation 3. The Vref is 0.8 V and the ISS current is 2 μA.

Equation 3. T S S ( m s ) = C S S ( n F ) × V R E F ( V ) I S S ( μ A )

The slow-start time must be set between 1 ms to 10 ms to make sure of good start-up behavior. The slow-start capacitor must be no more than 27 nF.

If during normal operation, the input voltage drops below the VIN UVLO threshold, or the EN pin is pulled below 1.25 V, or a thermal shutdown event occurs, the TPS54332 stops switching.