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參數(shù)資料
| 型號： | TPS2551DRVRG4 |
| 廠商： | TEXAS INSTRUMENTS INC |
| 元件分類： | 電源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO6 |
| 封裝： | GREEN, PLASTIC, SON-6 |
| 文件頁數(shù)： | 13/32頁 |
| 文件大?。?/td> | 1402K |
| 代理商： | TPS2551DRVRG4 |
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SELF-POWERED AND BUS-POWERED HUBS
LOW-POWER BUS-POWERED AND HIGH-POWER BUS-POWERED FUNCTIONS
USB POWER-DISTRIBUTION REQUIREMENTS
SLVS736B – FEBRUARY 2008 – REVISED NOVEMBER 2008 ........................................................................................................................................ www.ti.com
devices depending on its maximum current draw. A device classified as low-power can draw up to 100 mA as
defined by the standard. A device classified as high-power can draw up to 500 mA. It is important that the
minimum current-limit threshold of the current-limiting power-switch exceed the maximum current-limit draw of
the intended application. The latest USB standard should always be referenced when considering the
current-limit threshold
The USB specification defines two types of devices as hubs and functions. A USB hub is a device that contains
multiple ports for different USB devices to connect and can be self-powered (SPH) or bus-powered (BPH). A
function is a USB device that is able to transmit or receive data or control information over the bus. A USB
function can be embedded in a USB hub. A USB function can be one of three types included in the list below.
Low-power, bus-powered function
High-power, bus-powered function
Self-powered function
SPHs and BPHs distribute data and power to downstream functions. The TPS2550/51 has higher current
capability than required for a single USB port allowing it to power multiple downstream ports.
A SPH has a local power supply that powers embedded functions and downstream ports. This power supply
must provide between 4.75 V to 5.25 V to downstream facing devices under full-load and no-load conditions.
SPHs are required to have current-limit protection and must report overcurrent conditions to the USB controller.
Typical SPHs are desktop PCs, monitors, printers, and stand-alone hubs.
A BPH obtains all power from an upstream port and often contains an embedded function. It must power up with
less than 100 mA. The BPH usually has one embedded function, and power is always available to the controller
of the hub. If the embedded function and hub require more than 100 mA on power up, the power to the
embedded function may need to be kept off until enumeration is completed. This is accomplished by removing
power or by shutting off the clock to the embedded function. Power switching the embedded function is not
necessary if the aggregate power draw for the function and controller is less than 100 mA. The total current
drawn by the bus-powered device is the sum of the current to the controller, the embedded function, and the
downstream ports, and it is limited to 500 mA from an upstream port.
Both low-power and high-power bus-powered functions obtain all power from upstream ports. Low-power
functions always draw less than 100 mA; high-power functions must draw less than 100 mA at power up and can
draw up to 500 mA after enumeration. If the load of the function is more than the parallel combination of 44
and 10
F at power up, the device must implement inrush current limiting.
USB can be implemented in several ways regardless of the type of USB device being developed. Several
power-distribution features must be implemented.
SPHs must:
–
Current-limit downstream ports
–
Report overcurrent conditions
BPHs must:
–
Enable/disable power to downstream ports
–
Power up at <100 mA
–
Limit inrush current (<44
and 10
F)
Functions must:
–
Limit inrush currents
–
Power up at <100 mA
The feature set of the TPS2550/51 meets each of these requirements. The integrated current-limiting and
overcurrent reporting is required by self-powered hubs. The logic-level enable and controlled rise times meet the
need of both input and output ports on bus-powered hubs and the input ports for bus-powered functions.
20
Copyright 2008, Texas Instruments Incorporated
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相關代理商/技術參數(shù) |
參數(shù)描述 |
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| TPS2551DRVT | 功能描述:電源開關 IC - USB Adj Crnt-Ltd Pwr Dist Sw RoHS:否 制造商:Micrel 電源電壓-最小:2.7 V 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:SOIC-8 封裝:Tube |
| TPS2551DRVTG4 | 功能描述:電源開關 IC - USB Adj current Ltd Sw RoHS:否 制造商:Micrel 電源電壓-最小:2.7 V 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:SOIC-8 封裝:Tube |
| TPS2551QDBVRQ1 | 功能描述:電源開關 IC - USB Adj Crnt-Limited Pwr Distribution Sw RoHS:否 制造商:Micrel 電源電壓-最小:2.7 V 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:SOIC-8 封裝:Tube |
| TPS2552DBV1EVM-364 | 功能描述:交換機 IC 開發(fā)工具 TPS2552DBV1EVM-364 Eval Mod RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:USB Power Switches 工具用于評估:MAX4984E 工作電源電壓:2.8 V to 5.5 V |
| TPS2552DBVEVM-364 | 功能描述:交換機 IC 開發(fā)工具 TPS2552DBVEVM-364 Eval Mod RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:USB Power Switches 工具用于評估:MAX4984E 工作電源電壓:2.8 V to 5.5 V |
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