JAJSRQ0A October   2023  – February 2024 TPS274C65CP

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Switching Characteristics
    7. 6.7 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Pin Diagrams
      2. 8.3.2 Programmable Current Limit
      3. 8.3.3 Protection Mechanisms
        1. 8.3.3.1 Over-current Protection
        2. 8.3.3.2 Short-Circuit Protection
          1. 8.3.3.2.1 VS During Short-to-Ground
        3. 8.3.3.3 Thermal Shutdown Behavior
        4. 8.3.3.4 Inductive-Load Switching-Off Clamp
        5. 8.3.3.5 Inductive Load Demagnetization
        6. 8.3.3.6 Thermal Shutdown
        7. 8.3.3.7 Undervoltage Protection on VS (UVP)
        8. 8.3.3.8 Undervoltage Lockout on Low Voltage Supply (VDD_UVLO)
        9. 8.3.3.9 Power-Up and Power-Down Behavior
      4. 8.3.4 Diagnostic Mechanisms
        1. 8.3.4.1 Fault Indication
        2. 8.3.4.2 Short-to-Battery and Open-Load Detection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Off
      2. 8.4.2 Active
  10. 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 IEC 61000-4-5 Surge
        2. 9.2.2.2 Loss of GND
        3. 9.2.2.3 Paralleling Channels
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 ドキュメントの更新通知を受け取る方法
    3. 10.3 サポート・リソース
    4. 10.4 Trademarks
    5. 10.5 静電気放電に関する注意事項
    6. 10.6 用語集
  12. 11Revision History
  13. 12Mechanical, 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

8.3.3.4 Inductive-Load Switching-Off Clamp

When an inductive load is switching off, the output voltage is pulled down to negative, due to the inductance characteristics. The power FET may break down if the voltage is not clamped during the current-decay period. To protect the power FET in this situation, internally clamp the drain-to-source voltage, namely VDS,clamp, the clamp diode between the drain and gate.

Equation 1. VDS,Clamp = VS – VOUT

During the current-decay period (TDECAY), the power FET is turned on for inductance-energy dissipation. Both the energy of the power supply (ES) and the load (ELOAD) are dissipated on the high-side power switch itself, which is called EHSD. If resistance is in series with inductance, some of the load energy is dissipated in the resistance.

Equation 2. EHSD = ES + ELOAD = ES + EL – ER

From the high-side power switch’s view, EHSD equals the integration value during the current-decay period.

Equation 3. GUID-87664A16-486A-4B92-99DD-CC043FE7984D-low.gif
Equation 4. GUID-A298B928-F6B0-41C1-A51F-2AF954E741F2-low.gif
Equation 5. GUID-21066C26-F031-4A4B-B756-4800F6B75597-low.gif

When R approximately equals 0, EHSD can be given simply as:

Equation 6. GUID-C7E46332-DD3C-4B51-8522-0FBC69EF27B3-low.gif
GUID-4D1C0551-26BA-4CAF-92DB-3DBC632B84A3-low.svgFigure 8-10 Driving Inductive Load
GUID-08163EAD-4487-4AAA-966E-9E9347C6937B-low.svgFigure 8-11 Inductive-Load Switching-Off Diagram

As discussed previously, when switching off, supply energy and load energy are dissipated on the high-side power switch, which leads to the large thermal variation. For each high-side power switch, the upper limit of the maximum safe power dissipation depends on the device intrinsic capacity, ambient temperature, and board dissipation condition.