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参数资料
| 型号： | LM3420M5X-16.8/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| 封装： | MINIATURE, SOT-23, 5 PIN |
| 文件页数： | 4/17页 |
| 文件大小： | 441K |
| 代理商： | LM3420M5X-16.8/NOPB |
V
REG External Voltage Trim
(Continued)
Formulas for selecting trim resistor values are shown below,
based on the percent of increase (%incr) or percent of
decrease (%decr) of the output voltage from the nominal
voltage.
For LM3420-4.2
R
increase = 22x10
5/%incr
R
decrease = (53x10
5/%decr) 75x103
For LM3420-8.2
R
increase = 26x10
5/%incr
R
decrease = (150x10
5/%decr) 176x103
For LM3420-8.4
R
increase = 26x10
5/%incr
R
decrease = (154x10
5/%decr) 181x103
For LM3420-12.6
R
increase = 28x10
5/%incr
R
decrease = (259x10
5/%decr) 287x103
For LM3420-16.8
R
increase = 29x10
5/%incr
R
decrease = (364x10
5/%decr) 392x103
Application Information
The LM3420 regulator/driver provides the reference and
feedback drive functions for a Lithium-Ion battery charger. It
can be used in many different charger configurations using
both linear and switching topologies to provide the precision
needed for charging Lithium-Ion batteries safely and effi-
ciently. Output voltage tolerances better than 0.5% are pos-
sible without using trim pots or precision resistors. The cir-
cuits shown are designed for 2 cell operation, but they can
readily be changed for either 1, 3 or 4 cell charging applica-
tions.
One item to keep in mind when designing with the LM3420 is
that there are parasitic diodes present. In some designs,
under special electrical conditions, unwanted currents may
flow. Parasitic diodes exist from OUT to IN, as well as from
GROUND to IN. In both instances the diode arrow is pointed
toward the IN pin.
Application Circuits
The circuit shown in Figure 5 performs constant-current,
constant-voltage charging of two Li-Ion cells. At the begin-
ning of the charge cycle, when the battery voltage is less
than 8.4V, the LM3420 sources no current from the OUT pin,
keeping Q2 off, thus allowing the LM317 Adjustable voltage
regulator to operate as a constant-current source. (The
LM317 is rated for currents up to 1.5A, and the LM350 and
LM338 can be used for higher currents.) The LM317 forces
a constant 1.25V across R
LIM, thus generating a constant
current of
I
LIM = 1.25V/RLIM
01235909
Increasing V
REG
01235910
Decreasing V
REG
FIGURE 4. Changing V
REG
01235901
FIGURE 5. Constant Current/Constant Voltage Li-Ion Battery Charger
LM3420-4.2/LM3420-8.2/LM3420-8.4/LM3420-12.6/LM3420-16.8
www.national.com
12
相关PDF资料 |
PDF描述 |
|---|---|
| LM3420AM5-4.2/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3420M5-8.4/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3420M5-8.2/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3420AM5X-8.4/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3460-1.5MWC | 1-OUTPUT THREE TERM VOLTAGE REFERENCE, 1.5 V, UUC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM3420M5X-4.2 | 功能描述:IC CTRLR LI-ION BAT CHRG SOT23-5 RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:1 系列:- 功能:充电管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:3.75 V ~ 6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商设备封装:SOT-23-5 包装:剪切带 (CT) 产品目录页面:669 (CN2011-ZH PDF) 其它名称:MCP73831T-2ACI/OTCT |
| LM3420M5X-8.2 | 功能描述:IC CTRLR LI-ION BAT CHRG SOT23-5 RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:1 系列:- 功能:充电管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:3.75 V ~ 6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SC-74A，SOT-753 供应商设备封装:SOT-23-5 包装:剪切带 (CT) 产品目录页面:669 (CN2011-ZH PDF) 其它名称:MCP73831T-2ACI/OTCT |
| LM3420M5X-8.4 | 功能描述:电池管理 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 |
| LM3420M5X-8.4/NOPB | 功能描述:电池管理 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 |
| LM3421 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:N-Channel Controllers for Constant Current LED Drivers |
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