JAJSEY6B March   2018  – October 2018 TPS7A10

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      ドロップアウト 対 IOUTおよび温度、YKAパッケージ
      2.      代表的なアプリケーション回路
  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 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 Excellent Transient Response
      2. 7.3.2 Global Undervoltage Lockout (UVLO)
      3. 7.3.3 Active Discharge
      4. 7.3.4 Enable
      5. 7.3.5 Sequencing Requirement
      6. 7.3.6 Internal Foldback Current Limit
      7. 7.3.7 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Mode
      2. 7.4.2 Dropout Mode
      3. 7.4.3 Disable Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Recommended Capacitor Types
      2. 8.1.2 Input and Output Capacitor Requirements
      3. 8.1.3 Load Transient Response
      4. 8.1.4 Dropout Voltage
      5. 8.1.5 Behavior During Transition From Dropout Into Regulation
      6. 8.1.6 Undervoltage Lockout Circuit Operation
      7. 8.1.7 Power Dissipation (PD)
        1. 8.1.7.1 Estimating Junction Temperature
        2. 8.1.7.2 Recommended Area for Continuous Operation
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input Current
        2. 8.2.2.2 Thermal Dissipation
      3. 8.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11デバイスおよびドキュメントのサポート
    1. 11.1 デバイス・サポート
      1. 11.1.1 開発サポート
        1. 11.1.1.1 評価モジュール
        2. 11.1.1.2 Spiceモデル
      2. 11.1.2 デバイスの項目表記
    2. 11.2 ドキュメントのサポート
      1. 11.2.1 関連資料
    3. 11.3 ドキュメントの更新通知を受け取る方法
    4. 11.4 コミュニティ・リソース
    5. 11.5 商標
    6. 11.6 静電気放電に関する注意事項
    7. 11.7 Glossary
  12. 12メカニカル、パッケージ、および注文情報

7.3.6 Internal Foldback Current Limit

The internal foldback current limit circuit is used to protect the LDO against high-load current faults or shorting events. The foldback mechanism lowers the current limit as the output voltage decreases, and limits power dissipation during short-circuit events while still allowing for the device to operate at the rated output current; see Figure 15.

For example, when VOUT is 90% of VOUT(nom), the current limit is ICL (typical); however, if VOUT is forced to 0 V, the current limit is ISC (typical).

In many LDOs, the foldback current limit can prevent start up into a constant-current load or a negatively-biased output. A brick-wall current limit is when there is an abrupt current stop after the current limit is reached. The foldback mechanism for this device goes into a brick-wall current limit when VOUT > 500 mV (typical), thus limiting current to ICL (typical). When VOUT is approximately 0 V, current is limited to ISC (typical) in order to provide normal start up into a variety of loads.

Thermal shutdown can activate during a current-limit event because of the high power dissipation typically found in these conditions. To provide proper operation of the current limit, minimize the inductances to the input and load. Continuous operation in current limit is not recommended.