JAJSE14B October   2017  – November 2017 TPS23525

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
  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 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
  7. 7 Parameter Measurement Information
    1. 7.1 Relationship between Sense Voltage, Gate Current, and Timer
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Current Limit
        1. 8.3.1.1 Programming the CL Switch-Over Threshold
        2. 8.3.1.2 Programming CL1
        3. 8.3.1.3 Programming CL2
        4. 8.3.1.4 Computing the Fast Trip Threshold
      2. 8.3.2 Soft Start Disconnect
      3. 8.3.3 Timer
      4. 8.3.4 OR-ing
    4. 8.4 Device Functional Modes
      1. 8.4.1 OFF State
      2. 8.4.2 Insertion Delay State
      3. 8.4.3 Start-up State
      4. 8.4.4 Normal Operation State
  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  Selecting RSNS
        2. 9.2.2.2  Selecting Soft Start Setting: CSS and CSS,VEE
        3. 9.2.2.3  Selecting VDS Switch Over Threshold
        4. 9.2.2.4  Timer Selection
        5. 9.2.2.5  MOSFET Selection and SOA Checks
        6. 9.2.2.6  Input Cap, Input TVS, and OR-ing FET selection
        7. 9.2.2.7  EMI Filter Consideration
        8. 9.2.2.8  Under Voltage and Over Voltage Settings
        9. 9.2.2.9  Choosing RVCC and CVCC
        10. 9.2.2.10 Power Good Interface to Downstream DC/DC
      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

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

8.3.1 Current Limit

The TPS23525 utilizes two current limit thresholds:

  • ICL1 – also referred to as high current limit threshold, which is used when the VDS of the hot swap FET is low.
  • ICL2 – lower current limit threshold, which is used when the VDS of the hot swap FET is high.

This dual level protection scheme ensures that the part has a higher chance of riding out voltage steps and other transients due to the higher current limit at low VDS, while protecting the MOSFET during start into short and hot-short events, by setting a lower current limit threshold for conditions with high VDS. The transition threshold is programmed with a resistor that is connected from the drain of the hot swap FET to the D pin of the TPS23525. The figure below illustrates an example with a ICL1 set to 25 A and ICL2 set to 3 A. Note that compared to a traditional SOA protection scheme this approach allows better utilization of the SOA in the 10 V < VDS. < 40-V range, which is critical in riding through transients and voltage steps.

Note that in both cases the TPS23525 regulated the gate voltage to enforce the current limit. However, this regulation is not very fast and doesn’t offer the best protection against hot-shorts on the output. To protect in this scenario a fast comparator is used, which quickly pulls down the gate in case of severe over current events (2x bigger than VCL1).

TPS23525 tps23523_dual_current_limit_vs_FET_.gifFigure 8. Dual Current Limit vs FET Power Limit