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参数资料
| 型号： | TPS2220BDBG4 |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO24 |
| 封装： | GREEN, PLASTIC, SSOP-24 |
| 文件页数： | 13/31页 |
| 文件大小： | 774K |
| 代理商： | TPS2220BDBG4 |
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12-V SUPPLY NOT REQUIRED
VOLTAGE-TRANSITIONING REQUIREMENT
SHUTDOWN MODE
POWER-SUPPLY CONSIDERATIONS
TPS2220B
SLVS554 – JANUARY 2005
APPLICATION INFORMATION (continued)
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. Excessive current generates an error signal that limits
the output current of only the affected output, preventing damage to the host. Each AVCC output overcurrent
limits from 1 A to 2.0 A, typically around 1.6 A; the AVPP outputs limit from 100 mA to 250 mA, typically around
200 mA.
Second, when an overcurrent condition is detected, the TPS2220B asserts an active low OC signal that can be
monitored by the microprocessor or controller to initiate diagnostics and/or send the user a warning message. If
an overcurrent condition persists, causing the IC to exceed its maximum junction temperature, thermal-protection
circuitry activates, shutting down all power outputs until the device cools to within a safe operating region, which
is ensured by a thermal shutdown hysteresis. Thermal limiting prevents destruction of the IC from overheating
beyond the package power-dissipation ratings.
During power up, the devices control the rise times of the AVCC and AVPP outputs and limit the inrush current
into a large load capacitance, faulty card, or connector.
Some PC Card switches use the externally supplied 12 V to power gate drive and other chip functions, which
requires that power be present at all times. The TPS2220B offers considerable power savings by using an
internal charge pump to generate the required higher gate drive voltages from the 3.3-V input. Therefore, the
external 12-V supply can be disabled except when needed by the PC Card in the slot, thereby extending battery
lifetime. A special feature in the 12-V circuitry actually helps to reduce the supply current demanded from the
3.3-V input. When 12 V is supplied and requested at the VPP output, a voltage selection circuit draws the
charge-pump drive current for the 12-V FETs from the 12-V input. This selection is automatic and effectively
reduces demand fluctuations on the normal 3.3-V VCC rail. For proper operation of this feature, a minimum 3.3-V
input capacitance of 4.7 F is recommended, and a minimum 12-V input ramp-up rate of 12 V/50 ms (240 V/s) is
required. Additional power savings are realized during a software shutdown in which quiescent current drops to a
maximum of 1 A.
PC Cards, like portables, are migrating from 5 V to 3.3 V to minimize power consumption, optimize board space,
and increase logic speeds. The TPS2220B meets all combinations of power delivery as currently defined in the
PCMCIA 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 its 3.3-V compatibility. The PCMCIA specification requires that the capacitors on
3.3-V-compatible cards be discharged to below 0.8 V before applying 3.3-V power. This action ensures that
sensitive 3.3-V circuitry is not subjected to any residual 5-V charge and functions as a power reset. PC Card
specification requires that VCC be discharged within 100 ms. PC Card resistance cannot 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 devices include discharge transistors on all AVCC and AVPP outputs to meet
the specification requirement.
In the shutdown mode, which can be controlled by SHDN or bit D8 of the input serial DATA word, each of the
AVCC and AVPP outputs is forced to a high-impedance state. In this mode, the chip quiescent current is reduced
to 1 A or less to conserve battery power.
The devices has multiple pins for 5-V power input and for the switched AVCC output. Any individual pin can
conduct the rated input or output current. Unless all pins are connected in parallel, the series resistance is higher
than that specified, resulting in increased voltage drops and power loss. It is recommended that all input and
output power pins be paralleled for optimum operation.
To increase the noise immunity of the TPS2220B the power-supply inputs should be bypassed with at least a
4.7-F electrolytic or tantalum capacitor paralleled by a 0.047-F to 0.1-F ceramic capacitor. It is strongly
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| TPS2220BDBR | 功能描述:热插拔功率分布 Single PC Card Ser Intfc Pwr 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 |
| TPS2220BDBRG4 | 功能描述:热插拔功率分布 Single PC Card Ser Intfc Pwr 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 |
| TPS2220BPWP | 功能描述:热插拔功率分布 Single PC Card Ser Intfc Pwr 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 |
| TPS2220BPWPG4 | 功能描述:热插拔功率分布 Single PC Card Ser Intfc Pwr 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 |
| TPS2220BPWPR | 功能描述:热插拔功率分布 Single PC Card Ser Intfc Pwr 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 |
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