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参数资料
| 型号： | TPS2228PWPG4 |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | 电源管理 |
| 英文描述： | 3-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO20 |
| 封装： | GREEN, PLASTIC, HTSSOP-20 |
| 文件页数： | 8/30页 |
| 文件大小： | 696K |
| 代理商： | TPS2228PWPG4 |
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TPS2228
TPS2221
SLVS419A MAY 2002 REVISED SEPTEMBER 2002
www.ti.com
16
APPLICATION INFORMATION
OVERVIEW
PC cards were initially introduced as a means to add
EEPROM (flash memory) to portable computers with
limited onboard memory. The idea of add-in cards quickly
took hold; modems, wireless LANs, GPS systems,
multimedia, and hard-disk versions were soon available.
As the number of PC card applications grew, the
engineering community quickly recognized the need for a
standard to ensure compatibility across platforms. As a
result, the PCMCIA (Personal Computer Memory Card
International Association) was established, comprised of
members from leading computer, software, PC card, and
semiconductor manufacturers. One key goal was to
realize the plug-and-play concept, so that cards and hosts
from different vendors could communicate with one
another transparently.
PC CARD POWER SPECIFICATION
The current PC card standard set forth by the PCMCIA
committee states that power is to be transferred between
the host and the card through eight of the PC card
connector’s 68 terminals. This power interface consists of
two VCC, two VPP/VCORE, and four ground terminals.
Multiple
power
and
ground
terminals
minimize
connector-terminal and line resistance. The two Vpp/
Vcore terminals were originally specified as separate
signals, but the host is no longer required to provide
separate programmable voltages on each pin. Primary
power for the card is supplied through the VCC terminals;
flash- memory programming and erase voltage is supplied
through the VPP/VCORE terminals. The VPP/VCORE
terminals are also intended to be used as a supplemental
source of power, such as a core voltage for integrated
circuits.
OVERCURRENT AND OVER TEMPERATURE
PROTECTION
PC cards are inherently subject to damage caused by
mishandling. Host systems require protection against
short-circuited cards that could lead to power supply or
PCB trace damage. Even systems sufficiently robust to
withstand a short circuit would still undergo rapid battery
discharge into the damaged PC card, resulting in the
rather sudden and unacceptable loss of system power.
The TPS2228/2221 power interface switch is designed to
respond quickly to an overcurrent condition to protect the
system. During an overcurrent event, the current limit
circuit of the TPS2228/2221 generates an internal error
signal that linearly limits the output current of the affected
output. The propogation delay associated with activating
the current-limit circuit has an effect on the amount of
current initially delivered to the output. During this time, the
input voltage to the switch may droop a small amount. The
amount of voltage droop is system dependent. Power
supply bulk capacitors play an important role in minimizing
this voltage droop.
Overcurrent sensing is applied to each output separately.
As a result, only the affected output is current-limited
during an overcurrent event. The TPS2228/2221 also has
an overcurrent status output (OC) that is asserted low to
provide feedback that an overcurrent condition has
occurred.
The TPS2228/2221 has two thermal shutdown circuits.
The higher thermal shutdown circuit protects the device
from a high junction temperature condition. In the event
that the junction temperature exceeds a minimum of
155
°C, the higher thermal shutdown circuit turns off all
switches to protect the device. Normal switch operation
resumes when the junction temperature cools down
approximately 10
°C.
In the event of an overcurrent condition, the lower thermal
shutdown circuit activates when the junction temperature
exceeds a minimum of 120
°C. On the TPS2221, this lower
thermal shutdown circuit disables both the VCC and the
VPP/VCORE switches once the junction temperature
exceeds the lower thermal trip point. On the TPS2228,
only the channel in overcurrent (either AVCC and
AVPP/VCORE, or BVCC and BVPP/VCORE) is disabled. For
both the TPS2221 and the TPS2228, normal operation of
the switches resumes once the junction temperature cools
down approximately 10
°C. This cycle continues until the
overcurrent condition is removed.
VOLTAGE TRANSISTIONING REQUIREMENT
PC cards, like portables, are migrating from 5 V to 3.3 V
and even 1.8 V to minimize power consumption, optimize
board
space,
and
increase
logic
speeds.
The
TPS2228/2221 power interface switch is designed to meet
all combinations of power delivery as currently defined in
the PC card standard. The latest protocol accommodates
mixed 3.3 V/ 5 V systems by first powering the card with
5 V, then polling it to determine if it is compatible with 3.3-V
power. The PC card standard requires that the capacitors
on 3.3-V compatible cards be discharged to below 0.8 V
before applying 3.3 V power. This ensures that sensitive
3.3-V circuitry is not subjected to any residual 5-V charge
and functions as a power reset. The PC card standard
requires that VCC be discharged within 100 ms. PC card
resistance can not be relied on to provide a discharge path
for voltages stored on PC card capacitance because of
possible high-impedance isolation by power-management
schemes. The TPS2228/2221 power interface switch
includes discharge transistors on all VCC and VPP/VCORE
outputs to meet the specification requirement.
相关PDF资料 |
PDF描述 |
|---|---|
| TPS2221PWP | 3-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO14 |
| TPS2228PWPR | 3-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO20 |
| TPS2228DBRG4 | 3-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO30 |
| TPS2223PWPR | 3-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO24 |
| TPS2223PWPG4 | 3-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO24 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| TPS2228PWPR | 功能描述:热插拔功率分布 1A Dual-Slot CardBay w/Serial Interface RoHS:否 制造商:Texas Instruments 产品:Controllers & Switches 电流限制: 电源电压-最大:7 V 电源电压-最小:- 0.3 V 工作温度范围: 功率耗散: 安装风格:SMD/SMT 封装 / 箱体:MSOP-8 封装:Tube |
| TPS2228PWPRG4 | 功能描述:热插拔功率分布 1A Dual-Slot CardBay w/Serial Interface RoHS:否 制造商:Texas Instruments 产品:Controllers & Switches 电流限制: 电源电压-最大:7 V 电源电压-最小:- 0.3 V 工作温度范围: 功率耗散: 安装风格:SMD/SMT 封装 / 箱体:MSOP-8 封装:Tube |
| TPS2231EVM | 功能描述:电源管理IC开发工具 TPS2231 Eval Mod RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| TPS2231MRGPR | 功能描述:热插拔功率分布 ExpressCard Sgl Pwr Interface Sw RoHS:否 制造商:Texas Instruments 产品:Controllers & Switches 电流限制: 电源电压-最大:7 V 电源电压-最小:- 0.3 V 工作温度范围: 功率耗散: 安装风格:SMD/SMT 封装 / 箱体:MSOP-8 封装:Tube |
| TPS2231MRGPR-1 | 功能描述:热插拔功率分布 ExpressCard Sgl Pwr Interface Sw RoHS:否 制造商:Texas Instruments 产品:Controllers & Switches 电流限制: 电源电压-最大:7 V 电源电压-最小:- 0.3 V 工作温度范围: 功率耗散: 安装风格:SMD/SMT 封装 / 箱体:MSOP-8 封装:Tube |
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