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參數(shù)資料
| 型號： | TPS2376DDAR-H |
| 廠商： | TEXAS INSTRUMENTS INC |
| 元件分類： | 電源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
| 封裝： | GREEN, PLASTIC, POWER PAD, SOIC-8 |
| 文件頁數(shù)： | 2/23頁 |
| 文件大小： | 640K |
| 代理商： | TPS2376DDAR-H |
www.ti.com
INTERNAL THRESHOLDS
Operational
Mode
Detection
Classification
PD Powered
Idle
1.4V
V(CL_ON)
V(CU_OFF)
V(CU_H)
V(UVLO_F)
V(UVLO_R)
V(VDD)
DETECTION
CLASSIFICATION
UNDERVOLTAGE LOCKOUT (UVLO)
SLVS646A – SEPTEMBER 2006 – REVISED SEPTEMBER 2006
APPLICATION INFORMATION (continued)
In order to implement the defined PoE functions shown in Figure 12, the TPS2376-H has a number of internal
comparators with hysteresis for stable switching between the various states. Figure 13 relates the parameters in
the Electrical Characteristics section to the PoE states. The mode labeled idle between classification and PD
powered implies that the DET, CLASS, PG, and RTN pins are all high impedance.
Figure 13. Threshold Voltages
The 25 k
PD signature is measured by applying two voltages between 2.7 V to 10.1 V, that are at least 1 V
apart, to the PD's PI and measuring the current. The resistance is calculated as a
V/I, with an acceptable
range of 23.75 k
to 26.25 k.
The TPS2376-H is in detection mode whenever the supply voltage is below the lower classification threshold.
The TPS2376-H draws a minimum of bias power in this condition, while PG and RTN are high impedance and
the circuits associated with ILIM and CLASS are disabled. The DET pin is pulled to VSS during detection.
The classification process applies a voltage between 14.5 V and 20.5 V, for a maximum of 75 ms, to the input of
the PD, which in turn draws a fixed current set by R(CLASS). An 802.3af PSE measures the PD current to
determine which of the five available classes (Table 1) that the PD is signaling. The total current drawn from the
PSE during classification is the sum of bias currents and current through R(CLASS). The TPS2376-H disconnects
R(CLASS) at voltages above the classification range to avoid excessive power dissipation (Figure 12 and
A high power end-to-end system may choose to not implement classification, or redefine the power associated
with each class. Low-voltage systems, for example 24 V, may not be able to use CLASS because the
operational voltage may lie within the classification voltage range. This would cause the TPS2376-H
classification circuits to dissipate power continuously.
The power rating of the class resistor should be chosen so that it is not overstressed for the required 75-ms
classification period, during which 10 V is applied. A higher wattage resistor might be required to withstand
testing over longer time periods.
The TPS2376-H incorporates an undervoltage lockout (UVLO) circuit that monitors line voltage to determine
when to apply power to the downstream load and allow the PD to power up. The IEEE 802.3af specification
dictates a maximum PD turn on voltage of 42 V and a minimum turn-off voltage of 30 V (Figure 13). The UVLO
pin provides the flexibility to adjust the turn on and turn off to the IEEE 802.3af limits, or a custom set. Design
the turn-on for 39.5 V if a design which uses the IEEE 802.3af limits is desired.
10
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TPS2376DDAR-HG4 | 功能描述:熱插拔功率分布 IEEE 802.3af PoE Hi Pwr PD CONTROLLER RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
| TPS2376DG4 | 功能描述:熱插拔功率分布 IEEE 802.3af PoE Pwr Device Cntrler RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
| TPS2376DR | 功能描述:熱插拔功率分布 IEEE 802.3af PoE Pwr Device Cntrler RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
| TPS2376DRG4 | 功能描述:熱插拔功率分布 IEEE 802.3af PoE Pwr Device Cntrler RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
| TPS2376HEVM | 功能描述:電源管理IC開發(fā)工具 TPS2376H Evaluation Module RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
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