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

9.2.2.1 Input Bridges and Schottky Diodes

Using Schottky diodes instead of PN junction diodes for the PoE input bridges and DVDD will reduce the loss of this function by about 30%. However, there are some things to consider when using them.

The IEEE standard specifies a maximum backfeed voltage of 2.8 V. A 100-kΩ resistor is placed between the unpowered pairs and the voltage is measured across the resistor. Schottky diodes often have a higher reverse leakage current than PN diodes, making this a harder requirement to meet. Use conservative design for diode operating temperature, select lower-leakage devices where possible, and match leakage and temperatures by using packaged bridges to help with this.

Schottky diode leakage current and lower dynamic resistance can impact the detection signature. Setting reasonable expectations for the temperature range over which the detection signature is accurate is the simplest solution. Increasing RDEN slightly may also help meet the requirement.

Schottky diodes have proven less robust to the stresses of ESD transients, failing as a short or becoming leaky. Take care to provide adequate protection in line with the exposure levels. This protection may be as simple as ferrite beads and capacitors.

A general recommendation for the input rectifiers are 1 A or 2 A, 100-V rated discrete or bridge diodes.