JAJSFC9B September   2017  – June 2018 TPS560430

UNLESS OTHERWISE NOTED, this document contains 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、1100kHz、PFM
  4. 4 改訂履歴
  5. 5 Device Comparison Table
  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 Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 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 Fixed Frequency Peak Current Mode Control
      2. 8.3.2 Adjustable Output Voltage
      3. 8.3.3 Enable
      4. 8.3.4 Minimum ON-Time, Minimum OFF-Time and Frequency Foldback
      5. 8.3.5 Bootstrap Voltage
      6. 8.3.6 Over Current and Short Circuit Protection
      7. 8.3.7 Soft Start
      8. 8.3.8 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Active Mode
      3. 8.4.3 CCM Mode
      4. 8.4.4 Light-Load Operation (PFM Version)
      5. 8.4.5 Light-Load Operation (FPWM Version)
  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 Custom Design With WEBENCH® Tools
        2. 9.2.2.2 Output Voltage Set-Point
        3. 9.2.2.3 Switching Frequency
        4. 9.2.2.4 Inductor Selection
        5. 9.2.2.5 Output Capacitor Selection
        6. 9.2.2.6 Input Capacitor Selection
        7. 9.2.2.7 Bootstrap Capacitor
        8. 9.2.2.8 Under Voltage Lockout Set-Point
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Compact Layout for EMI Reduction
      2. 11.1.2 Feedback Resistors
    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 開発サポート
        1. 12.1.1.1 WEBENCH®ツールによるカスタム設計
    2. 12.2 ドキュメントのサポート
      1. 12.2.1 関連資料
    3. 12.3 ドキュメントの更新通知を受け取る方法
    4. 12.4 コミュニティ・リソース
    5. 12.5 商標
    6. 12.6 静電気放電に関する注意事項
    7. 12.7 Glossary
  13. 13メカニカル、パッケージ、および注文情報

パッケージ・オプション

デバイスごとのパッケージ図は、PDF版データシートをご参照ください。

メカニカル・データ（パッケージ｜ピン）
  • DBV|6
サーマルパッド・メカニカル・データ
発注情報

9.2.2.4 Inductor Selection

The most critical parameters for the inductor are the inductance, saturation current and the RMS current. The inductance is based on the desired peak-to-peak ripple current ΔiL. Since the ripple current increases with the input voltage, the maximum input voltage is always used to calculate the minimum inductance LMIN. Use Equation 9 to calculate the minimum value of the output inductor. KIND is a coefficient that represents the amount of inductor ripple current relative to the maximum output current of the device. A reasonable value of KIND should be 20% to 60%. During an instantaneous over current operation event, the RMS and peak inductor current can be high. The inductor current rating should be a bit higher than current limit.

Equation 8. TPS560430 slvse22-equation-8.gif
Equation 9. TPS560430 slvse22-equation-9.gif

In general, it is preferable to choose lower inductance in switching power supplies, because it usually corresponds to faster transient response, smaller DCR, and reduced size for more compact designs. But too low of an inductance can generate too large of an inductor current ripple such that over current protection at the full load could be falsely triggered. It also generates more inductor core loss since the current ripple is larger. Larger inductor current ripple also implies larger output voltage ripple with same output capacitors. With peak current mode control, it is not recommended to have too small of an inductor current ripple. A larger peak current ripple improves the comparator signal to noise ratio.

For this design example, choose KIND = 0.4, the minimum inductor value is calculated to be 16.3 µH. Choose the nearest standard 18-µH ferrite inductor with a capability of 1-A RMS current and 1.5-A saturation current.