JAJSOM3A may   2022  – march 2023 TPS62903-Q1

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Mode Selection and Device Configuration MODE/S-CONF
      2. 8.3.2  Adjustable VO Operation (External Voltage Divider)
      3. 8.3.3  Selectable VO Operation (VSET and Internal Voltage Divider)
      4. 8.3.4  Soft Start and Tracking (SS/TR)
        1. 8.3.4.1 Tracking Function
      5. 8.3.5  Smart Enable with Precise Threshold
      6. 8.3.6  Power Good (PG)
      7. 8.3.7  Output Discharge Function
      8. 8.3.8  Undervoltage Lockout (UVLO)
      9. 8.3.9  Current Limit and Short-Circuit Protection
      10. 8.3.10 High Temperature Specifications
      11. 8.3.11 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Forced Pulse Width Modulation (FPWM) Operation
      2. 8.4.2 Power Save Mode Operation (Auto PFM and PWM)
      3. 8.4.3 AEE (Automatic Efficiency Enhancement)
      4. 8.4.4 100% Duty-Cycle Operation
      5. 8.4.5 Starting into a Prebiased Load
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application with Adjustable Output Voltage
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Custom Design With WEBENCH® Tools
        2. 9.2.2.2 Programming the Output Voltage
        3. 9.2.2.3 External Component Selection
          1. 9.2.2.3.1 Output Filter and Loop Stability
          2. 9.2.2.3.2 Inductor Selection
          3. 9.2.2.3.3 Capacitor Selection
            1. 9.2.2.3.3.1 Output Capacitor
            2. 9.2.2.3.3.2 Input Capacitor
            3. 9.2.2.3.3.3 Soft-Start Capacitor
      3. 9.2.3 Application Curves
        1. 9.2.3.1 Application Curves Vout = 1.8 V
        2. 9.2.3.2 Application Curves Vout = 1.2 V
        3. 9.2.3.3 Application Curves Vout = 0.6 V
    3. 9.3 Typical Application with Selectable VOUT using VSET
      1. 9.3.1 Design Requirements
      2. 9.3.2 Detailed Design Procedure
        1. 9.3.2.1 Programming the Output Voltage
      3. 9.3.3 Application Curves
        1. 9.3.3.1 Application Curves Vout = 5 V
        2. 9.3.3.2 Application Curves Vout = 3.3 V
    4. 9.4 System Examples
      1. 9.4.1 LED Power Supply
      2. 9.4.2 Powering Multiple Loads
      3. 9.4.3 Voltage Tracking
      4. 9.4.4 Inverting Buck-Boost (IBB)
    5. 9.5 Power Supply Recommendations
    6. 9.6 Layout
      1. 9.6.1 Layout Guidelines
      2. 9.6.2 Layout Example
      3. 9.6.3 Thermal Considerations
  10. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 サード・パーティ製品に関する免責事項
      2. 10.1.2 Development Support
        1. 10.1.2.1 Custom Design With WEBENCH® Tools
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 ドキュメントの更新通知を受け取る方法
    4. 10.4 サポート・リソース
    5. 10.5 Trademarks
    6. 10.6 静電気放電に関する注意事項
    7. 10.7 用語集
  11. 11Mechanical, 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

8.4.4 100% Duty-Cycle Operation

The duty cycle of the buck converter operating in PWM mode is given as D = VOUT / VIN. The duty cycle increases as the input voltage comes close to the output voltage and the off time gets smaller. When the minimum off time of typically 80 ns is reached, the TPS62903-Q1 scales down its switching frequency while it approaches 100% mode. In 100% mode, the device keeps the high-side switch on continuously. The high-side switch stays turned on as long as the output voltage is below the internal set point, allowing the conversion of small input to output voltage differences (for example, getting longest operation time of battery-powered applications). In 100% duty cycle mode, the low-side FET is switched off.

The minimum input voltage to maintain output voltage regulation, depending on the load current and the output voltage level, can be calculated as:

Equation 10. V I N   ( M I N ) = V O U T + I O U T × R D S ( O N )   +   R L

where

  • IOUT is the output current.
  • RDS(on) is the on-state resistance of the high-side FET.
  • RL is the DC resistance of the inductor used.