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參數資料
| 型號： | LP3945 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Battery Charge Management System |
| 中文描述： | 電池充電管理系統(tǒng) |
| 文件頁數： | 8/15頁 |
| 文件大小： | 337K |
| 代理商： | LP3945 |
Application Notes
LP3945 CHARGER OPERATION
The LP3945 is a complete battery charger with I
2
C interface.
Charge cycle is initiated with wall adaptor insertion. If the
wall adaptor voltage appearing on the CHG-IN pin meets
under-voltage (V
UVLO-TSHD
), over-voltage (V
OVLO-TSHD
), and
the Adaptor OK signal is detected, then pre-conditioning
process begins (see
Figure 1
). In pre-qualification cycle, a
safe current level, less than 65 mA, is pumped into the
battery while the voltage across the battery terminals is
measured. Once this voltage exceeds 3.0V, the controller
will initiate constant current fast charge cycle. During this
cycle, the 5.6 hr safety timer is started and charge current is
increased to I
. The default value for I
is set during
manufacturing to 500 mA but it is user programmable from
500 mA to 950 mA in 50 mA step. The programmed current
is determined by battery type and manufacturers’ recom-
mendation.
If safety timer times out during constant current cycle, charg-
ing will be terminated if StopModeEN pin is pulled high. If it
is pulled low, device will proceed to operate in maintenance
mode and have to be interrupted externally. This is not a
recommended mode of operation. Disabling the 5.6hr timer
can potentially expose the battery to prolong charge cycle
and damage the battery. If StopModeEN feature is used,
user must protect the battery from exposure to prolong
charge cycle.
As the battery is charged during constant current mode, the
voltage across pack terminal increases until it reaches 4.1V
(or 4.2V). As soon as pack terminal exceeds 4.1V (or 4.2V),
controller starts operating in constant voltage mode by ap-
plying regulated V
BATT
voltage across the battery terminal.
During this cycle, charge current, I
CHG
, continues to de-
crease with time and when it drops below 0.1C (by default),
the EOC signal is activated indicating successful completion
of the charge cycle. The "C" term in 0.1C is the programmed
I
CHG
. For example, 0.1C of 700mA is 70mA, and 0.2C of
700mA is 140mA. EOC current can be programmed to 0.1C,
0.15C, or 0.2C. The default value is 0.1C. After completing
the full charge cycle, controller will start maintenance cycle
where battery pack voltage is monitored continuously. If
during the maintenance cycle, pack voltage drops below
3.9V, charge cycle will be initiated providing that the wall
adaptor is plugged in and is alive.
Ni-MH charge mode (LP3945 only), which is a constant
voltage mode charging, can be selected by setting the
“mode” bit to HIGH via the I
2
C interface.
The LP3945 with I
2
C programming allows maximum flexibil-
ity in selecting charge current, battery regulation voltage
(4.1V or 4.2V), EOC current and battery type (Li Ion or
Ni-MH). The LP3945 operates in default mode during power
up. See the “I
2
C Interface” section for more detail.
LP3946 CHARGER OPERATION
The LP3946 is a simpler version of the LP3945. It does not
have any I
2
C interface, thus the device operates on default
setting. The values in
BOLD
in
Table 1
are the default
settings. Default settings can be set at the factory to custom-
er’s specifications. For other options, please contact a Na-
tional Semiconductor sales office.
The LP3946 charges only Li Ion type battery.
TABLE 1. LP3946 Performance Options
Battery Voltage
Regulation (V)
4.1
4.2
End of Charge Current
Threshold (mA)
0.1C
0.15C
0.20C
Charge
Current (mA)
500
550
600
650
700
750
800
850
900
950
20066510
FIGURE 1. Charger Power Up and Power Down Waveform
L
www.national.com
8
相關PDF資料 |
PDF描述 |
|---|---|
| LP3945ILD | Battery Charge Management System |
| LP3945ILDX | Battery Charge Management System |
| LP3961ES-1.8 | 800mA Fast Ultra Low Dropout Linear Regulators |
| LP3961ES-2.5 | 800mA Fast Ultra Low Dropout Linear Regulators |
| LP3961ES-3.3 | 800mA Fast Ultra Low Dropout Linear Regulators |
相關代理商/技術參數 |
參數描述 |
|---|---|
| LP3945ILD | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Battery Charge Management System |
| LP3945ILDX | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Battery Charge Management System |
| LP3945LD | 功能描述:IC MANAGEMENT BATT CHARGE 14-LLP RoHS:否 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:1 系列:- 功能:充電管理 電池化學:鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:3.75 V ~ 6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SC-74A，SOT-753 供應商設備封裝:SOT-23-5 包裝:剪切帶 (CT) 產品目錄頁面:669 (CN2011-ZH PDF) 其它名稱:MCP73831T-2ACI/OTCT |
| LP3946 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Battery Charge Management System |
| LP3946ILDX | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Battery Charge Management System |
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