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參數(shù)資料
| 型號： | LTC4070IDDB#TRPBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 電源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
| 封裝： | 3 X 2 MM, 0.75 MM HEIGHT, LEAD FREE, PLASTIC, MO-229WECD-1, DFN-8 |
| 文件頁數(shù)： | 15/16頁 |
| 文件大?。?/td> | 214K |
| 代理商： | LTC4070IDDB#TRPBF |
LTC4070
8
4070fc
operaTion
Forexample,iftheNTCthermistorrequiresthefloatvoltage
to be dropped by 100mV (ADJ = VCC and 0.29VNTCBIAS
< VNTC < 0.36VNTCBIAS) then the HBO rising threshold
is detected when VCC rises past VFLOAT – DVFLOAT(NTC) –
VHBTH = 4.2V – 100mV – 40mV = 4.06V. The HBO falling
threshold in this case is detected when VCC falls below
VFLOAT – DVFLOAT(NTC) – VHBTH – VHBHY = 4.2V – 100mV
– 40mV – 100mV = 3.96V.
Low Battery Status Output: LBO
When the battery voltage drops below 3.2V, the LBO pin
pulls high. Otherwise, the LBO pin pulls low when the
battery voltage exceeds about 3.5V.
Whilethelowbatteryconditionpersists,NTCandADJpins
are no longer sampled—the functions are disabled—and
total supply consumption for the LTC4070 drops to less
than 300nA (typ).
General Charging Considerations
The LTC4070 uses a different charging methodology from
previous chargers. Most Li-Ion chargers terminate the
charging after a period of time. The LTC4070 does not have
a discrete charge termination. Extensive measurements
on Li-Ion cells show that the cell charge current drops to
nanoamps with the shunt charge control circuit effectively
terminatingthecharge.Forlongcelllife,operatethecharger
at 100mV lower charge voltage normally used.
The simplest application of the LTC4070 is shown in
Figure 1. This application requires only an external resis-
tor to program the charge/shunt current. Assume the wall
adapter voltage (VWALL) is 12V and the minimum battery
voltage (VBAT_MIN) is 3V, then the maximum charge cur-
rent is calculated as:
IMAX_CHARGE =
VWALL VBAT_MIN
(
)
RIN
=
12V 3V
(
)
162Ω
= 55.5mA
Care must be taken in selecting the input resistor. Power
dissipated in RIN under full charge current is given by the
following equation:
PDISS =
VWALL VBAT_MIN
(
)
2
RIN
=
12V 3V
(
)
2
162Ω
= 0.5W
The charge current decreases as the battery voltage
increases. If the rising battery voltage is 40mV less than
the programmed float voltage, the LTC4070 consumes
only 450nA of current, and all of the input current flows
into the battery. As the battery voltage reaches the
float voltage, the LTC4070 shunts current from the wall
adapter and regulates the battery voltage to VFLOAT. The
more shunt current the LTC4070 sinks, the less charge
current the battery gets. Eventually, the LTC4070 shunts
all the current from the battery; up to the maximum shunt
current. The maximum shunt current in this case, with no
NTC adjustment, is determined by the input resistor and
is calculated as:
ISHUNT_MAX =
VWALL VFLOAT
(
)
RIN
=
12V 4.1V
(
)
162Ω
= 49mA
At this point the power dissipated in the input resistor is
388mW.
Figure 1. Single-Cell Battery Charger
4070 F01
LTC4070
ADJ
RIN
162
0.5W
GND
12V WALL
ADAPTER
Li-Ion
BATTERY
NTCBIAS
FLOAT
IF NOT NEEDED
FLOAT
NTC
VCC
+
applicaTions inForMaTion
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC4070IMS8E | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Li-Ion/Polymer Shunt Battery Charger System |
| LTC4070IMS8E#PBF | 功能描述:IC BATT CHRGR LIION/POLY 8MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學(xué):鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4070IMS8E#TRPBF | 功能描述:IC BATT CHRGR LIION/POLY 8MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學(xué):鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4070IMS8EPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Li-Ion/Polymer Shunt Battery Charger System |
| LTC4070IMS8ETRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Li-Ion/Polymer Shunt Battery Charger System |
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