JAJSEO7I October   2008  – December 2017 TPS23754 , TPS23754-1 , TPS23756

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      TPS23754を使用する高効率コンバータ
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Electrical Characteristics: PoE and Control
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  APD
      2. 8.3.2  BLNK
      3. 8.3.3  CLS
      4. 8.3.4  Current Sense (CS)
      5. 8.3.5  Control (CTL)
      6. 8.3.6  Detection and Enable (DEN)
      7. 8.3.7  DT
      8. 8.3.8  Frequency and Synchronization (FRS)
      9. 8.3.9  GATE
      10. 8.3.10 GAT2
      11. 8.3.11 PPD
      12. 8.3.12 RTN, ARTN, COM
      13. 8.3.13 T2P
      14. 8.3.14 VB
      15. 8.3.15 VC
      16. 8.3.16 VDD
      17. 8.3.17 VDD1
      18. 8.3.18 VSS
      19. 8.3.19 PowerPAD
    4. 8.4 Device Functional Modes
      1. 8.4.1 PoE Overview
        1. 8.4.1.1  Threshold Voltages
        2. 8.4.1.2  PoE Start-Up Sequence
        3. 8.4.1.3  Detection
        4. 8.4.1.4  Hardware Classification
        5. 8.4.1.5  Inrush and Start-Up
        6. 8.4.1.6  Maintain Power Signature
        7. 8.4.1.7  Start-Up and Converter Operation
        8. 8.4.1.8  PD Hotswap Operation
        9. 8.4.1.9  Converter Controller Features
        10. 8.4.1.10 Bootstrap Topology
        11. 8.4.1.11 Current Slope Compensation and Current Limit
        12. 8.4.1.12 Blanking – RBLNK
        13. 8.4.1.13 Dead Time
        14. 8.4.1.14 FRS and Synchronization
        15. 8.4.1.15 T2P, Start-Up, and Power Management
        16. 8.4.1.16 Thermal Shutdown
        17. 8.4.1.17 Adapter ORing
        18. 8.4.1.18 PPD ORing Features
        19. 8.4.1.19 Using DEN to Disable PoE
        20. 8.4.1.20 ORing Challenges
  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  Input Bridges and Schottky Diodes
        2. 9.2.2.2  Protection, D1
        3. 9.2.2.3  Capacitor, C1
        4. 9.2.2.4  Detection Resistor, RDEN
        5. 9.2.2.5  Classification Resistor, RCLS
        6. 9.2.2.6  Dead Time Resistor, RDT
        7. 9.2.2.7  Switching Transformer Considerations and RVC
        8. 9.2.2.8  Special Switching MOSFET Considerations
        9. 9.2.2.9  Thermal Considerations and OTSD
        10. 9.2.2.10 APD Pin Divider Network, RAPD1, RAPD2
        11. 9.2.2.11 PPD Pin Divider Network, RPPD1, RPPD2
        12. 9.2.2.12 Setting Frequency (RFRS) and Synchronization
        13. 9.2.2.13 Current Slope Compensation
        14. 9.2.2.14 Blanking Period, RBLNK
        15. 9.2.2.15 Estimating Bias Supply Requirements and CVC
        16. 9.2.2.16 T2P Pin Interface
        17. 9.2.2.17 Advanced ORing Techniques
        18. 9.2.2.18 Soft Start
        19. 9.2.2.19 Frequency Dithering for Conducted Emissions Control
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 ESD
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 ドキュメントのサポート
      1. 12.1.1 関連資料
    2. 12.2 コミュニティ・リソース
    3. 12.3 商標
    4. 12.4 静電気放電に関する注意事項
    5. 12.5 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

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）
  • PWP|20
サーマルパッド・メカニカル・データ
発注情報

9.2.2.18 Soft Start

Converters require a soft start on the voltage error amplifier to prevent output overshoot on start-up. Figure 35 shows a common implementation of a secondary-side soft start that works with the typical TL431 error amplifier. The soft-start components consist of DSS, RSS, and CSS. They serve to control the output rate-of-rise by pulling VCTL down as CSS charges through ROB, the optocoupler, and DSS. This has the added advantage that the TL431 output and CIZ are preset to the proper value as the output voltage reaches the regulated value, preventing voltage overshoot due to the error amplifier recovery. The secondary-side error amplifier will not become active until there is sufficient voltage on the secondary. The TPS23754 device provides a primary-side soft start, which persists long enough (about 4 ms) for secondary side voltage-loop soft start to take over. The primary-side current-loop soft start controls the switching MOSFET peak current by applying a slowly rising ramp voltage to a second PWM control input. The PWM is controlled by the lower of the soft-start ramp or the CTL-derived current demand. The actual output voltage rise time is usually much shorter than the internal soft-start period. Initially the internal soft-start ramp limits the maximum current demand as a function of time. Either the current limit, secondary-side soft start, or output regulation assume control of the PWM before the internal soft-start period is over. Figure 24 shows a smooth handoff between the primary and secondary-side soft start with minimal output voltage overshoot.

TPS23754 TPS23754-1 TPS23756 soft_st_lvs885.gifFigure 35. Error Amplifier Soft Start