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参数资料
| 型号： | UCC3957MTR-1G4 |
| 厂商： | Texas Instruments |
| 文件页数： | 7/15页 |
| 文件大小： | 0K |
| 描述： | IC LI-ION PROTECT CIRCUIT 16QSOP |
| 标准包装： | 2,500 |
| 功能： | 过压/欠压保护 |
| 电池化学： | 锂离子（Li-Ion） |
| 电源电压： | 5 V ~ 20 V |
| 工作温度： | -20°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-SSOP（0.154"，3.90mm 宽） |
| 供应商设备封装： | 16-SSOP/QSOP |
| 包装： | 带卷 (TR) |
Not Recommended for New Designs
UCC3957 1, UCC3957 2, UCC3957 3, UCC3957 4
SLUS236B – JANUARY 1999 – REVISED SEPTEMBER 2002
APPLICATION INFORMATION
undervoltage protection
When any cell is found to be overdischarged (below the normal-to-undercharge threshold), the state machine
turns off both high-side FETs and enters the sleep mode, where current consumption drops to about 3.5 μ A.
It remains in sleep mode until the application of a charger is sensed by the wakeup pin (WU) being raised above
VDD.
charging
Once a charger has been applied, the charge FET is turned on as long as the charge-enable input pin (CHGEN)
is pulled up to the DVDD pin. If the CHGEN input is left open (or connected to AN4), the charge FET remains
off.
During charge, the charge and discharge FETs cycle on and off while the device is in the sleep state
(undercharge mode), until the cell voltages are all above the undercharge-to-normal threshold. Once the cell
voltages are above this threshold, the device enters the normal state and the FETs remain on continuously.
While the device is charging and in undercharge mode, there is an approximate on time of 8 ms corresponding
to one sampling period, with a very short off time corresponding to undercharge-voltage detect and sleep-mode;
once WU is pulled back up to PACK(+), wake-up detect again occurs, and a new sampling period/charge cycle
is initiated.
open wire protection
The UCC3957 provides protection against broken-cell sense connections within the pack. If the sense
connection to one of the cells (pins AN1, AN2, or AN3) should become disconnected, weak internal-current
sources make the cells that are connected to that wire appear to be in overcharge and charging of the pack is
prevented.
overvoltage protection and the smart discharge feature
If any cell is charged to a voltage exceeding the normal-to-overcharge threshold, the charge FET is turned off,
preventing further charge current. Hysteresis keeps the charge FET off until the cell voltages have dropped
below the overcharge-to-normal threshold. In most protector designs, the charge FET is held off completely
within this voltage band. During this time, discharge current must be conducted through the body diode of the
charge FET. This forward voltage drop can be as high as 1 V, causing significant power dissipation in the charge
FET and wasting precious battery power.
The UCC3957 has a unique smart discharge feature that allows the charge FET to return to on mode (for
discharge only) while still in the overcharge hysteresis band. This greatly reduces power dissipation in the
charge FET. This is accomplished by sensing the voltage drop across the current-sense resistor. If this drop
exceeds 15 mV (corresponding to 0.6 A of discharge current using a .025 ? sense resistor), the charge FET
is turned back on. This threshold assures that only discharge current is conducted. In an example using a
20-mW FET with a 1-V body diode drop and a 1-A load, the power dissipation in Q1 would be reduced from 1
W to 0.02 W.
NOTE: A similar technique is not used during charge (when the discharge MOSFET is off due to
cells being in undervoltage) because the charge current should be low while the cells are in
undervoltage.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| UCC3957MTR-2 | 功能描述:电池管理 3-4-Cell Lithium-Ion Protection IC RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| UCC3957MTR-2G4 | 功能描述:电池管理 3-4-Cell Lithium-Ion Protection IC RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| UCC3957MTR-3 | 功能描述:电池管理 3-4-Cell Lithium-Ion Protection IC RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| UCC3957MTR-3G4 | 功能描述:电池管理 3-4-Cell Lithium-Ion Protection IC RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| UCC3957MTR-4 | 功能描述:电池管理 3-4-Cell Lithium-Ion Protection IC RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
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