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参数资料
| 型号： | LTC4067EDE#TR |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO12 |
| 封装： | 4 X 3 MM, PLASTIC, MO-229WGED, DFN-12 |
| 文件页数： | 7/20页 |
| 文件大小： | 223K |
| 代理商： | LTC4067EDE#TR |
LTC4067
15
4067f
APPLICATIO S I FOR ATIO
WU
U
Battery Charger Stability Considerations
The LTC4067 battery charger contains two control loops:
constant voltage and constant current. The constant-volt-
age loop is stable without any compensation when a battery
is connected with low impedance leads. Excessive battery
lead length, however, may add enough series inductance
to require a bypass capacitor of at least 1μF from BAT to
ground. Furthermore, a 4.7μF capacitor with a 0.2Ω to 1Ω
series resistor is required from BAT to ground to keep the
ripple voltage low when the battery is disconnected.
In constant-current mode the PROG pin is in the feedback
loop, not the BAT pin. Because of the additional pole cre-
ated by PROG pin capacitance, additional capacitance on
this pin must be kept to a minimum. With no additional
capacitance on the PROG pin, the charger is stable with
program resistor values as high as 6k. However additional
capacitance on this node reduces the maximum allowed
program resistor. The pole frequency at the PROG pin
should be kept above 500kHz. Therefore, if the PROG pin
is loaded with a capacitance, CPROG, the following equa-
tion should be used to calculate the maximum resistance
value for RPROG:
RPROG ≤ 1/(2π 5 105 CPROG)
Average, rather than instantaneous, battery current may be
of interest to the user. For example, if a switching power
supply operating in low current mode is connected in
parallel with the battery, the average current being pulled
out of the BAT pin is typically of more interest than the
instantaneous current pulses. In such a case, a simple
RC lter at the PROG pin measures the average BAT pin
current, as shown in the gure below. A 20k resistor has
been added between the PROG pin and the lter capacitor
to ensure stability. This technique may also be used on
the CLPROG pin.
NTC Thermistor Input Pin
An NTC input provides the option of charge qualication
using battery temperature and an external thermistor
thermally coupled to the battery. When the thermistor
senses an over or under temperature condition, charg-
ing is suspended until the temperature returns to a safe
operating range. The CHRG pin ashes while this out of
temperature condition persists. If the NTC pin is grounded,
NTC charge qualication is disabled. For more informa-
tion on the CHRG pin during fault conditions see the Fault
Conditions heading.
The battery temperature is measured by placing a nega-
tive temperature coefcient (NTC) thermistor in thermal
contact with the battery. The thermal regulation feature
of the LTC4067, requires a thermistor, RNTC, between the
NTC pin and GND as well as a second resistor, RNOM, from
the NTC pin to IN. The recommended RNOM resistor has a
value equal to the value of the chosen NTC thermistor at
25°C. (For a Vishay NTHS0603N02N1002 thermistor this
value is 10k.) The LTC4067 charger goes into hold mode
when the resistance, RHOT, of the NTC thermistor drops
to 0.41 times the value of RNOM or approximately 4.1k,
which is at 50°C. Hold mode freezes the timer and stops
the charge cycle until the thermistor indicates a return to
a valid temperature range. As the temperature drops, the
resistance of the NTC thermistor rises. The LTC4067 is
also designed to go into hold mode when the value of the
Figure 2. Isolating Capacitive Load on PROG Pin and Filtering.
LTC4067
20k
AVERAGE
BATTERY
CURRENT
4067 F02
PROG
RPROG
CFILTER
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相关代理商/技术参数 |
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| LTC4068-4.2 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Standalone Linear Li-Ion Battery Charger with Programmable Termination |
| LTC4068EDD-4.2 | 功能描述:IC BATT CHARGER W/PROG TERM 8DFN RoHS:否 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
| LTC4068EDD-4.2#PBF | 功能描述:IC CHARGER BATT LI-ON 8-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
| LTC4068EDD-4.2#TR | 功能描述:IC BATT CHARGER W/PROG TERM 8DFN RoHS:否 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
| LTC4068EDD-4.2#TRPBF | 功能描述:IC BATT CHARGER W/PROG TERM 8DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
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