JAJSH01 February   2019 TPS65295

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     代表的なアプリケーション
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Pin Configuration and Functions
    1.     Pin 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 PWM Operation and D-CAP3 Control
      2. 8.3.2 Advanced Eco-mode Control
      3. 8.3.3 Soft Start and Prebiased Soft Start
      4. 8.3.4 Power Good
      5. 8.3.5 Overcurrent Protection and Undervoltage Protection
      6. 8.3.6 Overvoltage Protection
      7. 8.3.7 UVLO Protection
      8. 8.3.8 Output Voltage Discharge
      9. 8.3.9 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Light Load Operation for VDDQ Buck and VPP Buck
      2. 8.4.2 Output State Control
      3. 8.4.3 Output Sequence Control
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 External Component Selection
          1. 9.2.2.1.1 Inductor Selection
          2. 9.2.2.1.2 Output Capacitor Selection
          3. 9.2.2.1.3 Input Capacitor Selection
          4. 9.2.2.1.4 Bootstrap Capacitor and Resistor Selection
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 デバイス・サポート
      1. 12.1.1 デベロッパー・ネットワークの製品に関する免責事項
    2. 12.2 ドキュメントの更新通知を受け取る方法
    3. 12.3 コミュニティ・リソース
    4. 12.4 商標
    5. 12.5 静電気放電に関する注意事項
    6. 12.6 Glossary
  13. 13メカニカル、パッケージ、および注文情報
    1. 13.1 Package Option Addendum
      1. 13.1.1 Packaging Information
      2. 13.1.2 Tape and Reel 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

8.3.2 Advanced Eco-mode™ Control

The VDDQ buck and VPP buck are designed with advanced Eco-mode™ control schemes to maintain high light load efficiency. As the output current decreases from heavy load conditions, the inductor current is also reduced and eventually comes to a point where the 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 it takes longer time to discharge the output capacitor with smaller load current to the level of the reference voltage. This makes the switching frequency lower, proportional to the load current, and keeps the light load efficiency high. The light load current where the transition to Eco-mode™ operation happens ( IOUT(LL) ) can be calculated from Equation 2.

Equation 2. TPS65295 EQ_IoutLL_SLVSD05.gif

After identifying the application requirements, design the output inductance (LOUT) so that the inductor peak-to-peak ripple current is approximately between 20% and 30% of the IOUT(max) (peak current in the application). It is also important to size the inductor properly so that the valley current does not hit the negative low-side current limit.