ZHCSHL4I October 2008 – December 2017 TPS23754 , TPS23754-1 , TPS23756
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3 Feature Description
- 7.4
Device Functional Modes
- 7.4.1
PoE Overview
- 7.4.1.1 Threshold Voltages
- 7.4.1.2 PoE Start-Up Sequence
- 7.4.1.3 Detection
- 7.4.1.4 Hardware Classification
- 7.4.1.5 Inrush and Start-Up
- 7.4.1.6 Maintain Power Signature
- 7.4.1.7 Start-Up and Converter Operation
- 7.4.1.8 PD Hotswap Operation
- 7.4.1.9 Converter Controller Features
- 7.4.1.10 Bootstrap Topology
- 7.4.1.11 Current Slope Compensation and Current Limit
- 7.4.1.12 Blanking – RBLNK
- 7.4.1.13 Dead Time
- 7.4.1.14 FRS and Synchronization
- 7.4.1.15 T2P, Start-Up, and Power Management
- 7.4.1.16 Thermal Shutdown
- 7.4.1.17 Adapter ORing
- 7.4.1.18 PPD ORing Features
- 7.4.1.19 Using DEN to Disable PoE
- 7.4.1.20 ORing Challenges
- 7.4.1
PoE Overview
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Input Bridges and Schottky Diodes
- 8.2.2.2 Protection, D1
- 8.2.2.3 Capacitor, C1
- 8.2.2.4 Detection Resistor, RDEN
- 8.2.2.5 Classification Resistor, RCLS
- 8.2.2.6 Dead Time Resistor, RDT
- 8.2.2.7 Switching Transformer Considerations and RVC
- 8.2.2.8 Special Switching MOSFET Considerations
- 8.2.2.9 Thermal Considerations and OTSD
- 8.2.2.10 APD Pin Divider Network, RAPD1, RAPD2
- 8.2.2.11 PPD Pin Divider Network, RPPD1, RPPD2
- 8.2.2.12 Setting Frequency (RFRS) and Synchronization
- 8.2.2.13 Current Slope Compensation
- 8.2.2.14 Blanking Period, RBLNK
- 8.2.2.15 Estimating Bias Supply Requirements and CVC
- 8.2.2.16 T2P Pin Interface
- 8.2.2.17 Advanced ORing Techniques
- 8.2.2.18 Soft Start
- 8.2.2.19 Frequency Dithering for Conducted Emissions Control
- 8.2.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文檔支持
- 12機械、封裝和可訂購信息
封裝選項
請參考 PDF 數據表獲取器件具體的封裝圖。
機械數據 (封裝 | 引腳)
- PWP|20
散熱焊盤機械數據 (封裝 | 引腳)
- PWP|20
訂購信息
8.2.2.13 Current Slope Compensation
The TPS23754 device provides a fixed internal compensation ramp that suffices for most applications. RS (see Figure 31) may be used if the internally provided slope compensation is not enough.
Most current-mode control papers and application notes define the slope values in terms of VPP / TS (peak ramp voltage / switching period). However, the electrical characteristics table specifies the slope peak (VSLOPE) based on the maximum (78%) duty cycle. Assuming that the desired slope, VSLOPE-D (in mV/period), is based on the full period, compute RS per the following equation where VSLOPE, DMAX, and ISL-EX are from the electrical characteristics table with voltages in mV, current in μA, and the duty cycle is unitless (for example, DMAX = 0.78).
Figure 31. Additional Slope Compensation
CS may be required if the presence of RS causes increased noise, due to adjacent signals like the gate drive, to appear at the CS pin.