JAJS177F November   2003  – February 2020 TPS2490 , TPS2491

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      代表的なアプリケーション
  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  VCC
      2. 7.3.2  SENSE
      3. 7.3.3  GATE
      4. 7.3.4  OUT
      5. 7.3.5  EN
      6. 7.3.6  VREF
      7. 7.3.7  PROG
      8. 7.3.8  TIMER
      9. 7.3.9  PG
      10. 7.3.10 GND
    4. 7.4 Device Functional Modes
      1. 7.4.1 Board Plug-In ()
      2. 7.4.2 TIMER and PG Operation ()
      3. 7.4.3 Action of the Constant Power Engine ()
      4. 7.4.4 Response to a Hard Output Short ( and )
      5. 7.4.5 Automatic Restart ()
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Alternative Inrush Designs
        1. 8.1.1.1 Gate Capacitor (dV/dt) Control
        2. 8.1.1.2 PROG Inrush Control
      2. 8.1.2 Additional Design Considerations
        1. 8.1.2.1 Use of PG
        2. 8.1.2.2 Faults and Backplane Voltage Droop
        3. 8.1.2.3 Output Clamp Diode
        4. 8.1.2.4 Gate Clamp Diode
        5. 8.1.2.5 High Gate Capacitance Applications
        6. 8.1.2.6 Input Bypass
        7. 8.1.2.7 Output Short Circuit Measurements
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Select RSNS and CL setting
        2. 8.2.2.2 Selecting the Hot Swap FET(s)
        3. 8.2.2.3 Select Power Limit
        4. 8.2.2.4 Set Fault Timer
        5. 8.2.2.5 Check MOSFET SOA
        6. 8.2.2.6 Set Under-Voltage Threshold
        7. 8.2.2.7 Choose R5, and CIN
        8. 8.2.2.8 Input and Output Protection
        9. 8.2.2.9 Final Schematic and Component Values
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 PC Board Guidelines
      2. 10.1.2 System Considerations
    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 開発サポート
    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 関連リンク
    4. 11.4 ドキュメントの更新通知を受け取る方法
    5. 11.5 コミュニティ・リソース
    6. 11.6 商標
    7. 11.7 静電気放電に関する注意事項
    8. 11.8 Glossary
  12. 12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）
  • DGS|10
サーマルパッド・メカニカル・データ
発注情報

7.4.3 Action of the Constant Power Engine (Figure 14)

The calculated power dissipated in Q1, VDS ×ID, is computed under the same startup conditions as Figure 13 . The current of Q1, labeled IIN, initially rises to the value that satisfies the constant power engine; in this case it is
34 W ÷ 48 V = 0.7 A. The 34 W value is programmed into the engine by setting the PROG voltage using Equation 2 given in the PROG. VDS of Q1, which is calculated as V(SENSE–OUT), falls as CO charges, thus allowing the Q1 drain current to increase. This is the result of the internal constant power engine adjusting the current limit reference to the GATE amplifier as CO charges and VDS falls. The calculated device power in Figure 14, labeled FET PWR, is seen to be flat-topped and constant within the limitations of circuit tolerance and acquisition noise. A fixed current limit is implemented by clamping the constant power engine’s output to 50 mV when VDS is low. This protection technique can be viewed as a specialized form of foldback limiting; the benefit over linear foldback is that it yields the maximum output current from a device over the full range of VDS and still protects the device.

TPS2490 TPS2491 m1_stress_lvs503.gifFigure 14. Computation of Q1 Stress During Startup