JAJSES8B October   2017  – November 2018 TPS2372

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      概略回路図
  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 PG Power Good (Converter Enable) Pin Interface
      2. 7.3.2 CLSA and CLSB Classification, AUTCLS
      3. 7.3.3 DEN Detection and Enable
      4. 7.3.4 Internal Pass MOSFET and Inrush Delay Enable, IRSHDL_EN
      5. 7.3.5 TPH, TPL and BT PSE Type Indicators
      6. 7.3.6 AMPS_CTL, MPS_DUTY and Automatic MPS
      7. 7.3.7 VDD Supply Voltage
      8. 7.3.8 VSS
      9. 7.3.9 Exposed Thermal PAD
    4. 7.4 Device Functional Modes
      1. 7.4.1  PoE Overview
      2. 7.4.2  Threshold Voltages
      3. 7.4.3  PoE Startup Sequence
      4. 7.4.4  Detection
      5. 7.4.5  Hardware Classification
      6. 7.4.6  Autoclass
      7. 7.4.7  Inrush and Startup
      8. 7.4.8  Maintain Power Signature
      9. 7.4.9  Startup and Converter Operation
      10. 7.4.10 PD Hotswap Operation
      11. 7.4.11 Startup and Power Management, PG and TPH, TPL, BT
      12. 7.4.12 Using DEN to Disable PoE
  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 Requirements
        1. 8.2.2.1  Input Bridges and Schottky Diodes
        2. 8.2.2.2  Protection, D1
        3. 8.2.2.3  Capacitor, C1
        4. 8.2.2.4  Detection Resistor, RDEN
        5. 8.2.2.5  Classification Resistors, RCLSA and RCLSB
        6. 8.2.2.6  Opto-isolators for TPH, TPL and BT
        7. 8.2.2.7  Automatic MPS and MPS Duty Cycle, RMPS and RMPS_DUTY
        8. 8.2.2.8  Internal Voltage Reference, RREF
        9. 8.2.2.9  Autoclass
        10. 8.2.2.10 Inrush Delay
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 EMI Containment
    4. 10.4 Thermal Considerations and OTSD
    5. 10.5 ESD
  11. 11デバイスおよびドキュメントのサポート
    1. 11.1 ドキュメントのサポート
      1. 11.1.1 関連リンク
      2. 11.1.2 関連資料
    2. 11.2 ドキュメントの更新通知を受け取る方法
    3. 11.3 コミュニティ・リソース
    4. 11.4 商標
    5. 11.5 静電気放電に関する注意事項
    6. 11.6 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）
  • RGW|20
サーマルパッド・メカニカル・データ
発注情報

7.4.8 Maintain Power Signature

The MPS is an electrical signature presented by the PD to assure the PSE that it is still present after operating voltage is applied. For a Type 1 or Type 2 PD, a valid MPS consists of a minimum dc current of 10 mA, or a 10-mA pulsed current for at least 75 ms every 325 ms, and an AC impedance lower than 26.3 kΩ in parallel with 0.05 μF. Only Type 1 and Type 2 PSEs monitor the AC MPS. A Type 1 or Type 2 PSE that monitors only the AC MPS may remove power from the PD.

To enable applications with stringent standby requirements, IEEE802.3bt introduced a significant change regarding the minimum pulsed current duration to assure the PSE will maintain power. This applies to all Type 3 and Type 4 PSEs, and the pulse duration is ~10% of what is required for Type 1 and 2 PSEs. The MPS current amplitude requirement for Class 5-8 PDs have also increased to 16 mA at the PSE end of the ethernet cable.

If the current through the RTN-to-VSS path is below ~28 mA, the TPS2372 automatically generates the MPS pulsed current through the AMPS_CTL output pin, the current amplitude being adjustable with an external resistor. The TPS2372 is also able to determine if the PSE is of Type 1-2 or Type 3-4, automatically adjusting the MPS pulse duration and duty-cycle. Note that the IEEE802.3bt requirement for the PD is applicable at the PSE end of the cable. That means that depending the cable length and other parameters including the bulk capacitance, a longer MPS duration may be required to ensure a valid MPS. For that purpose, the TPS2372 has 3 different selections of MPS pulse duration and duty-cycle, selectable through the MPS_DUTY input pin.

When DEN is used to force the hotswap switch off, the DC MPS will not be met. A PSE that monitors the DC MPS will remove power from the PD when this occurs.