JAJSE23C August   2017  – June 2019 TPS1H000-Q1

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      代表的なブロック図
      2.      自動再試行モードでの電流制限保護
  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 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Current Limit
      2. 7.3.2 DELAY Pin Configuration
        1. 7.3.2.1 Holding Mode
        2. 7.3.2.2 Latch-Off Mode
        3. 7.3.2.3 Auto-Retry Mode
      3. 7.3.3 Standalone Operation
      4. 7.3.4 Fault Truth Table
      5. 7.3.5 Full Diagnostics
        1. 7.3.5.1 Short-to-GND and Overload Detection
        2. 7.3.5.2 Open-Load Detection
          1. 7.3.5.2.1 Output On
          2. 7.3.5.2.2 Output Off
        3. 7.3.5.3 Short-to-Battery Detection
        4. 7.3.5.4 Thermal Fault Detection
          1. 7.3.5.4.1 Thermal Shutdown
          2. 7.3.5.4.2 Thermal Swing
          3. 7.3.5.4.3 Fault Report Holding
      6. 7.3.6 Full Protections
        1. 7.3.6.1 UVLO Protection
        2. 7.3.6.2 Inductive Load Switching Off Clamp
        3. 7.3.6.3 Loss-of-GND Protection
        4. 7.3.6.4 Loss-of-Power-Supply Protection
        5. 7.3.6.5 Reverse-Current Protection
        6. 7.3.6.6 MCU I/O Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Working Modes
        1. 7.4.1.1 Normal Mode
        2. 7.4.1.2 Standby Mode
        3. 7.4.1.3 Standby Mode With Diagnostics
  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
      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 ドキュメントの更新通知を受け取る方法
    2. 11.2 コミュニティ・リソース
    3. 11.3 商標
    4. 11.4 静電気放電に関する注意事項
    5. 11.5 Glossary
  12. 12メカニカル、パッケージ、および注文情報

7.3.1 Current Limit

A high-accuracy current limit allows high reliability of the design. It protects the load and the power supply from overstressing during short-circuit-to-GND or power-up conditions. The current limit can also save system cost by reducing the size of PCB traces and connectors, and the capacity of the preceding power stage.

When a current-limit threshold is reached, a closed loop activates immediately. The output current is clamped at the set value, and a fault is reported out. The device heats up due to the high power dissipation on the power FET.

The device has two current-limit thresholds.

  • Internal current limit – The internal current limit is fixed at ICL(int). Tie the CL pin directly to the device GND for large-transient-current applications.
  • External adjustable current limit – An external resistor is used to set the current-limit threshold. Use Equation 1 to calculate R(CL). VCL(th) is the internal band-gap voltage. K(CL) is the ratio of the output current and the current-limit set value. K(CL) is constant across temperature and supply voltage. The external adjustable current limit allows the flexibility to set the current-limit value by application.
Equation 1. TPS1H000-Q1 Equation-1.gif

Note that if using a GND network which causes a level shift between the device GND and board GND, the CL pin must be connected to the device GND.

For better protection from a hard short-to-GND condition (when the IN pin is enabled, a short to GND occurs suddenly), the device implements a fast-trip protection to turn off the output before the current-limit closed loop is set up. The fast-trip response time is less than 1 µs, typically. With this fast response, the device can achieve better inrush current-suppression performance.

TPS1H000-Q1 Current-Limit.gifFigure 13. Current Limit