JAJSQ82B November   2023  – July 2024 TPS548D26

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  Internal VCC LDO and Using an External Bias on the VCC and VDRV Pin
      2. 6.3.2  Input Undervoltage Lockout (UVLO)
        1. 6.3.2.1 Fixed VCC_OK UVLO
        2. 6.3.2.2 Fixed VDRV UVLO
        3. 6.3.2.3 Fixed PVIN UVLO
        4. 6.3.2.4 Enable
      3. 6.3.3  Set the Output Voltage
      4. 6.3.4  Differential Remote Sense and Feedback Divider
      5. 6.3.5  Start-Up and Shutdown
      6. 6.3.6  Loop Compensation
      7. 6.3.7  Set Switching Frequency and Operation Mode
      8. 6.3.8  Switching Node (SW)
      9. 6.3.9  Overcurrent Limit and Low-side Current Sense
      10. 6.3.10 Negative Overcurrent Limit
      11. 6.3.11 Zero-Crossing Detection
      12. 6.3.12 Input Overvoltage Protection
      13. 6.3.13 Output Undervoltage and Overvoltage Protection
      14. 6.3.14 Overtemperature Protection
      15. 6.3.15 Power Good
    4. 6.4 Device Functional Modes
      1. 6.4.1 Forced Continuous-Conduction Mode
      2. 6.4.2 Auto-Skip Eco-mode Light Load Operation
      3. 6.4.3 Powering the Device From a 12-V Bus
      4. 6.4.4 Powering the Device From a Split-Rail Configuration
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Application
      2. 7.2.2 Design Requirements
      3. 7.2.3 Detailed Design Procedure
        1. 7.2.3.1 Inductor Selection
        2. 7.2.3.2 Input Capacitor Selection
        3. 7.2.3.3 Output Capacitor Selection
        4. 7.2.3.4 VCC and VRDV Bypass Capacitor
        5. 7.2.3.5 BOOT Capacitor Selection
        6. 7.2.3.6 PG Pullup Resistor Selection
      4. 7.2.4 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
        1. 7.4.2.1 Thermal Performance on TPS548D26 Evaluation Board
  9. 8 Device and Documentation Support
    1. 8.1 ドキュメントの更新通知を受け取る方法
    2. 8.2 サポート・リソース
    3. 8.3 Trademarks
    4. 8.4 静電気放電に関する注意事項
    5. 8.5 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

6.4.2 Auto-Skip Eco-mode Light Load Operation

When the operation mode is set to DCM, the device automatically reduces the switching frequency at light-load conditions to maintain high efficiency. This section describes the operation in detail.

As the output current decreases from heavy load condition, the inductor current also decreases until the rippled valley of the inductor current touches zero level. Zero level is the boundary between the continuous-conduction and discontinuous-conduction modes. The synchronous MOSFET turns off when this zero inductor current is detected. As the load current decreases further, the converter runs into discontinuous-conduction mode (DCM). The on-time is maintained to a level approximately the same as during continuous-conduction mode operation so that discharging the output capacitor with a smaller load current to the level of the reference voltage requires more time. Calculate the transition point to the light-load operation IOUT(LL) (for example, the threshold between continuous- and discontinuous-conduction mode) using the following equation.

Equation 2. TPS548D26

where

  • fSW is the switching frequency

TI recommends using low ESR capacitors (such as ceramic capacitor) for skip-mode.