参数资料
型号: TPS2205IDF
厂商: TEXAS INSTRUMENTS INC
元件分类: 电源管理
英文描述: 3-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO30
封装: GREEN, PLASTIC, SSOP-30
文件页数: 11/30页
文件大小: 593K
代理商: TPS2205IDF
TPS2205
DUALSLOT PC CARD POWERINTERFACE SWITCH
FOR PARALLEL PCMCIA CONTROLLERS
SLVS128E OCTOBER 1995 REVISED JANUARY 2001
19
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
APPLICATION INFORMATION
output ground switches
Several PCMCIA power-distribution switches on the market do not have an active-grounding FET switch. These
devices do not meet the PC Card specification requiring a discharge of VCC 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. A method commonly shown to alleviate this
problem is to add to the switch output an external 100-k
resistor in parallel with the PC Card. Considering that
this is the only discharge path to ground, a timing analysis shows that the RC time constant delays the required
discharge time to more than 2 seconds. The only way to ensure timing compatibility with PC Card standards
is to use a power-distribution switch that has an internal ground switch, like that of the TPS22xx family, or add
an external ground FET to each of the output lines with the control logic necessary to select it.
In summary, the TPS2205 is a complete single-chip dual-slot PC Card power interface. It meets all currently
defined PCMCIA specifications for power delivery in 5-V, 3.3-V, and mixed systems, and offers a serial control
interface. The TPS2205 offers functionality, power savings, overcurrent and thermal protection, and fault
reporting in one 30-pin SSOP surface-mount package, for maximum value added to new portable designs.
power-supply considerations
The TPS2205 has multiple pins for each of its 3.3-V, 5-V, and 12-V power inputs and for the switched VCC
outputs. Any individual pin can conduct the rated input or output current. Unless all pins are connected in
parallel, the series resistance is significantly higher than that specified, resulting in increased voltage drops and
lost power. Both 12-V inputs must be connected for proper Vpp switching; it is recommended that all input and
output power pins be paralleled for optimum operation.
Although the TPS2205 is fairly immune to power input fluctuations and noise, it is generally considered good
design practice to bypass power supplies, typically with a 1-
F electrolytic or tantalum capacitor paralleled by
a 0.047-
F to 0.1-F ceramic capacitor. It is strongly recommended that the switched VCC and Vpp outputs be
bypassed with a 0.1-
F or larger capacitor; doing so improves the immunity of the TPS2205 to electrostatic
discharge (ESD). Care should be taken to minimize the inductance of PCB traces between the TPS2205 and
the load. High switching currents can produce large negative-voltage transients, which forward biases substrate
diodes, resulting in unpredictable performance. Similary, no pin should be taken below 0.3 V.
overcurrent and thermal protection
The TPS2205 uses sense FETs to check for overcurrent conditions in each of the VCC and Vpp outputs. Unlike
sense resistors or polyfuses, these FETs do not add to the series resistance of the switch; therefore, voltage
and power losses are reduced. Overcurrent sensing is applied to each output separately. When an overcurrent
condition is detected, only the power output affected is limited; all other power outputs continue to function
normally. The OC indicator, normally a logic high, is a logic low when any overcurrent condition is detected,
providing for initiation of system diagnostics and/or sending a warning message to the user.
During power up, the TPS2205 controls the rise time of the VCC and Vpp outputs and limits the current into a
faulty card or connector. If a short circuit is applied after power is established (e.g., hot insertion of a bad card),
current is initially limited only by the impedance between the short and the power supply. In extreme cases, as
much as 10 A to 15 A may flow into the short before the current limiting of the TPS2205 engages. If the VCC
or Vpp outputs are driven below ground, the TPS2205 may latch nondestructively in an off state. Cycling power
will reestablish normal operation.
Overcurrent limiting for the VCC outputs is designed to activate if powered up into a short in the range of
1 A to 2.2 A, typically at about 1.6 A. The Vpp outputs limit from 120 mA to 400 mA, typically around 280 mA.
The protection circuitry acts by linearly limiting the current passing through the switch rather than initiating a full
shutdown of the supply. Shutdown occurs only during thermal limiting.
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TPS2205IDBG4 3-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO30
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TPS2206ADAP 制造商:Texas Instruments 功能描述:IC 1.4A DUAL PWR INT SW 32TSSOP 制造商:Texas Instruments 功能描述:IC, 1.4A DUAL PWR INT SW 32TSSOP
TPS2206ADAPG4 功能描述:热插拔功率分布 1A Dual-Slot PC Card Pwr 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
TPS2206ADAPR 功能描述:热插拔功率分布 PC Card Power-Ifc Switch 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