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參數資料
| 型號： | LTC4070EMS8E#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： | LEAD FREE, PLASTIC, MSOP-8 |
| 文件頁數： | 4/16頁 |
| 文件大?。?/td> | 214K |
| 代理商： | LTC4070EMS8E#TRPBF |
LTC4070
12
4070fc
Typical applicaTions
The LTC4070 status pins have sufficient drive strength to
use with an LED, for a visual indication of charging status.
Consider the application in Figure 7, where red LED D1 is
connected to the LBO pin and turns off when the battery
voltage is below VLBTH. Note that LED D1 discharges the
batteryuntilVCCfallsbelowVLBTH.GreenLEDD2,connected
to the HBO pin turns on while the battery is charging. When
the battery voltage rises to within VHBTHofthefloatvoltage
including NTC qualification, VFLOAT_EFF, D2 turns off to
indicate that the battery is no longer charging. Optionally,
a low leakage diode D3 is placed between the cathode of
D2 and the battery. This diode stops D2 from discharging
the battery when the input supply is not present.
In this application, RIN = 205, is sized for a maximum
shunt current of 50mA that occurs at the maximum input
voltageof15VandtheminimumNTCqualifiedfloatvoltage
Figure 7. Single Cell Charger with LED Status and
NTC Qualified Float Voltage
of 3.8V, assuming the voltage drop on diode D3 is 1.1V.
Without the optional D3, RIN increases to 226.
Figure8illustratesanapplicationtoreplacethreeNiMHcells
with a single Li-Ion cell. This simple application replaces
the NiMH charging solution without the need for a charge
termination or cell balancing scheme. NiMH charging can
be done without termination, but that algorithm limits the
charge rate to C/10. The LTC4070 application allows the
Li-Ion battery to be charged faster without concern of
over-charging.
Figure 9, 12V Wall Adapter Charging with 205mA, il-
lustrates the use of an external PFET transistor to boost
the maximum shunt current. If the battery voltage is
3.6V the battery receives the full charge current of
about 205mA. If the battery temperature is below 40°C,
the float voltage rises to 4.1V (ADJ = floating) then Q1
and the LTC4070 shunts 192mA away from the battery.
Ifthebatterytemperaturerises,theshuntcurrentincreases
to regulate the float voltage 75mV lower per 10°C rise in
batterytemperature,asdescribedinTable1.Atamaximum
shunt current of 200mA the minimum float voltage is held
at 3.8V when the battery temperature is above 70°C.
This example illustrates an alternative use of a LED, D1, to
observe the HBO status pin. This LED turns on to provide
a visual indication that the battery is fully charged, and
shuntsabout1.5mAwhenthebatteryrisestowithin40mV
of the desired float voltage. LED D1 discharges the battery,
when no supply is present, until VCC falls by more than
VHBTH + VHBHY below the float voltage. When using an
LED with the HBO pin in this configuration, it is important
to limit the LED current with a resistor, RLED as shown.
OtherwisethestepincurrentthroughRINthatoccurswhen
the LED turns on may pull VCC below the HBO hysteresis.
To prevent that situation, the ratio of RIN to RLED should
be selected to meet the following relation:
RIN
RLED
VCC VLED
(
)< VHBHY 50mV
where VLED is the forward voltage drop of the LED and a
margin of 50mV is subtracted from the HBO hysteresis.
A VLED value of 1.1V is assumed for this example. Refer
to the LED data sheet for the forward voltage drop at the
applied current level.
Figure 8. Replace Three NiMH with Lithium
4070 F07
LTC4070
ADJ
HBO
LBO
D1
LTST
C190CKT
OPTIONAL
D3
BAS416
VIN = 8V TO 15V
D2
LTST
C190GKT
RNTC: NTHS0402N02N1002F 10k
GND
FLOAT
T
RNOM
10k
Li-Ion
NTCBIAS
NTC
VCC
VBAT = 4.1V
RLED1
1k
RLED2
1k
RIN
205
1W
+
4070 TA01a
LTC4070
ADJ
FLOAT
LBO
HBO
GND
T
RNOM
10k
Li-Ion
NTCBIAS
DRV
NTC
VCC
IIN = 500mA
+
RNTC = NTHS0402N02N1002F 10k
VBAT = 4.1V
Q1
DMP3015LSS
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相關代理商/技術參數 |
參數描述 |
|---|---|
| LTC4070IDDB | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Li-Ion/Polymer Shunt Battery Charger System |
| LTC4070IDDB#PBF | 制造商:Linear Technology 功能描述: |
| LTC4070IDDB#TRMPBF | 功能描述:IC BATT CHRGR LIION/POLY 8DFN 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: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 供應商設備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4070IDDB#TRPBF | 功能描述:IC BATT CHRGR LIION/POLY 8DFN 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: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 供應商設備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4070IDDBPBF | 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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