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參數(shù)資料
| 型號： | LP3947 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | USB/AC Adaptor, Single Cell Li-Ion Battery Charger IC |
| 中文描述： | 的USB / AC適配器，單節(jié)鋰離子電池充電器IC |
| 文件頁數(shù)： | 9/14頁 |
| 文件大?。?/td> | 649K |
| 代理商： | LP3947 |
Application Notes
(Continued)
CHARGE CURRENT SELECTION IN CONSTANT
CURRENT MODE
In the AC adaptor mode, the LP3947 is designed to provide
a charge current ranging from 100 mA to 750 mA, in steps of
50 mA, to support batteries with different capacity ratings.
The default value is 500 mA. No external resistor is required
to set the charge current in the LP3947. In the USB mode,
the LP3947 will initially charge with 100 mA(ISEL = high). By
setting the ISEL pin low, charge current can be programmed
to 500 mA. In addition, with ISEL = low, the charge current
can be programmed to different values via the I
2
C interface.
TABLE 1. Charge Current Selection in AC Adaptor/USB Mode
MODE Pin
HIGH
HIGH
LOW
LOW
ISEL Pin
HIGH
LOW
HIGH
LOW
Functions
AC Adaptor Mode
ISEL polarity is irrelevant. Default 500 mA charge current. Can be
reprogrammed via I
2
C.
USB Mode
100 mA charge current
Default 500 mA charge current. Can be reprogrammed via I
2
C.
BATTERY VOLTAGE SELECTION
The battery voltage regulation can be set to 4.1V or 4.2V by
default. Please refer to the Ordering Information table for
more detail.
END OF CHARGE (EOC) CURRENT SELECTION
The EOC thresholds can be programmed to 0.1C, 0.15C or
0.2C in the LP3947. The default value is 0.1C, which pro-
vides the highest energy storage, but at the expense of
longer charging time. On the other hand, 0.2C takes the
least amount of charging time, but yields the least energy
storage.
CHARGE CURRENT SENSE DIFFERENTIAL AMPLIFIER
The charge current is monitored across the internal 120 m
current sense resistor. The differential amplifier provides the
analog representation of the charge current. Charge current
can be calculated using the following equation:
Where voltage at Diff Amp output (V
DIFF
) is in volt, and
charge current (I
CHG
) is in amps.
Monitoring the Diff Amp output during constant voltage cycle
can provide an accurate indication of the battery charge
status and time remaining to EOC. This feature is particularly
useful during constant voltage mode. The current sense
circuit is operational in the LDO mode as well. It can be used
to monitor the system current consumption during testing.
LED CHARGE STATUS INDICATORS
The LP3947 is equipped with two open drain outputs to drive
a green LED and a red LED. These two LEDs work together
in combinations to indicate charge status or fault conditions.
Table 2
shows all the conditions.
20111009
FIGURE 4. Charge Current Monitoring Circuit (Diff-Amp)
L
www.national.com
9
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LP3947ISD-09 | 功能描述:電池管理 RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
| LP3947ISD-09/NOPB | 功能描述:電池管理 RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
| LP3947ISD-51 | 功能描述:電池管理 RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
| LP3947ISD-51/NOPB | 功能描述:電池管理 RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
| LP3947ISD-51EV | 功能描述:電源管理IC開發(fā)工具 LP3947 EVAL BOARD RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
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