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參數(shù)資料
| 型號(hào)： | AT43312A |
| 廠商： | Atmel Corp. |
| 英文描述： | Self- and Bus-powered USB Hub Controller(自供電和總線供電USB集線器控制器) |
| 中文描述： | 自和總線供電的USB集線器控制器（自供電和總線供電的USB集線器控制器） |
| 文件頁(yè)數(shù)： | 5/18頁(yè) |
| 文件大小： | 249K |
| 代理商： | AT43312A |
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AT43312A
5
Power Management
A hub is a high-powered device and is allowed to draw up
to 500 mA of current from the host or upstream hub. The
AT43312A chip itself and its external hub circuitry consume
much less than 100 mA. The AT43312A’s power manage-
ment logic works with external devices to detect
overcurrent and control power to the ports.
Overcurrent sensing is on a per port basis and is achieved
through the OVCx pins. Whenever the voltage at OVCx is
asserted, the AT43312A treats it as an overcurrent
condition. This could be caused by an overload, or even a
short circuit, and causes the AT43312A to set the port’s
PORT_OVER_CURRENT status bit and its
C_PORT_OVER_CURRENT status change bit. At the
same time, power to the offending port is shut off and its
STATx generates a square wave with a frequency of about
1 second.
An external device is needed to monitor the overcurrent
condition and perform the actual switching of the ports’
power under control of the AT43312A. The signals to con-
trol the external switches are the PWRx pins that are open
drain signals and require external pull-up resistors. Any
type of suitable switch or device is acceptable. However, it
should have a low-voltage drop across it even when the
port absorbs full-power. In its simplest form this switch can
be a P-channel MOSFET. One advantage of using a MOS-
FET switch is its very low-voltage drop and low-cost.
Each one of the AT43312A’s port has its own power control
pin which is asserted only when a SetPortFeature[PORT-
POWER] request is received from the host. PWRx is de-
asserted under the following conditions:
1.
Power-up
2.
Reset and initialization
3.
Overcurrent condition
4.
Requested by the host through a ClearPortFeature
[PORT_POWER] for ALL the ports
Self-powered Mode
In the self-powered mode, power to the downstream ports
must be supplied by an external power supply. This power
supply must be capable of supplying 500 mA per port for a
total of 2A.
The USB specifications require that the voltage drop at the
power switch and board traces be no more than 100 mV. A
good conservative maximum drop at the power switch itself
should be no more than 75 mV. Careful design and selec-
tion of the power switch and PC board layout is required to
meet the specifications. When using a MOSFET switch, its
resistance must be 140m
or less under worst case condi-
tions. A suitable MOSFET switch for an AT43312A based
hub is an integrated high side dual MOSFET switch such
as the Micrel MIC2526.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AT43312 | Self- and Bus- Powered USB Hub Controller |
| AT43320 | Full-speed USB Hub/Function Microcontroller |
| AT43DK301 | Low-Cost USB Hub Development Kit |
| AT43DK312A | USB Hub Development Kit |
| AT43USB320A-AC | Full-speed USB Microcontroller with an Embedded Hub |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AT43312A_06 | 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:Self- and Bus-Bus-powered USB Hub Controller |
| AT43312A-6AC | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:BUS CONTROLLER |
| AT43312A-6PC | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:BUS CONTROLLER |
| AT43312A-6SC | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:BUS CONTROLLER |
| AT43312A-AC | 功能描述:USB 接口集成電路 FULL FEATURED USB HUB CONTROLLER RoHS:否 制造商:Cypress Semiconductor 產(chǎn)品:USB 2.0 數(shù)據(jù)速率: 接口類型:SPI 工作電源電壓:3.15 V to 3.45 V 工作電源電流: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WLCSP-20 |
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