JAJSFQ3A July   2018  – September 2019 TPS56637

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      概略回路図
      2.      効率と出力電流との関係 VOUT = 5V
  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 Handling Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 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  The Adaptive On-Time Control and PWM Operation
      2. 7.3.2  Mode Selection
        1. 7.3.2.1 Eco-mode™ Control Scheme
        2. 7.3.2.2 FCCM Control
      3. 7.3.3  Soft Start and Pre-Biased Soft Start
      4. 7.3.4  Enable and Adjusting Undervoltage Lockout
      5. 7.3.5  Output Overcurrent Limit and Undervoltage Protection
      6. 7.3.6  Overvoltage Protection
      7. 7.3.7  UVLO Protection
      8. 7.3.8  Thermal Shutdown
      9. 7.3.9  Output Voltage Discharge
      10. 7.3.10 Power Good
    4. 7.4 Device Functional Modes
      1. 7.4.1 Standby Operation
      2. 7.4.2 Normal Operation
      3. 7.4.3 Light Load Operation
  8. 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 Output Voltage Resistors Selection
        2. 8.2.2.2 Output Filter Selection
        3. 8.2.2.3 Input Capacitor Selection
        4. 8.2.2.4 Bootstrap Capacitor Selection
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11デバイスおよびドキュメントのサポート
    1. 11.1 ドキュメントのサポート
      1. 11.1.1 関連資料
    2. 11.2 ドキュメントの更新通知を受け取る方法
    3. 11.3 コミュニティ・リソース
    4. 11.4 商標
    5. 11.5 静電気放電に関する注意事項
    6. 11.6 Glossary
  12. 12メカニカル、パッケージ、および注文情報
    1. 12.1 Package Option Addendum
      1. 12.1.1 Packaging Information
      2. 12.1.2 Tape and Reel Information

7.3.2.1 Eco-mode™ Control Scheme

When MODE pin is short to GND(≤10kΩ), the TPS56637 is set to Eco-mode™ control scheme to maintain high light load efficiency. As the output current decreases from heavy load condition, the inductor current is also reduced and eventually comes to a point that its rippled valley touches zero level, which is the boundary between continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when the zero inductor current is detected. As the load current further decreases the converter runs into discontinuous conduction mode. The on-time is kept almost the same as it was in the continuous conduction mode so that longer time is needed to discharge the output capacitor with smaller load current to the level of the reference voltage. This process makes the switching frequency lower, proportional to the load current, and keeps the light load efficiency high. The transition point to the light load operation IOUT(LL) current can be calculated by Equation 1.

Equation 1. TPS56637 equation-1-slvseg1.gif