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| 型号： | LTC4069EDC#TRMPBF |
| 厂商： | Linear Technology |
| 文件页数： | 12/18页 |
| 文件大小： | 0K |
| 描述： | IC CHARGER LI-ION 6-DFN |
| 标准包装： | 500 |
| 功能： | 充电管理 |
| 电池化学： | 锂离子（Li-Ion） |
| 电源电压： | 3.75 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 6-WFDFN 裸露焊盘 |
| 供应商设备封装： | 6-DFN-EP（2x2） |
| 包装： | 带卷 (TR) |
LTC4069
APPLICATIONS INFORMATION
Undervoltage Charge Current Limiting (UVCL)
The LTC4069 includes undervoltage charge (?V UVCL1 )
current limiting that prevents full charge current until the
input supply voltage exceeds approximately 220mV above
the battery voltage. This feature is particularly useful if the
LTC4069 is powered from a supply with long leads (or any
relatively high output impedance).
For example, USB-powered systems tend to have highly
variable source impedances (due primarily to cable
quality and length). A transient load combined with such
impedance can easily trip the UVLO threshold and turn the
charger off unless undervoltage charge current limiting
is implemented.
Consider a situation where the LTC4069 is operating under
normal conditions and the input supply voltage begins to
droop (e.g., an external load drags the input supply down).
If the input voltage reaches V BAT + ?V UVCL1 (approximately
220mV above the battery voltage), undervoltage charge
current limiting will begin to reduce the charge current
in an attempt to maintain ?V UVCL1 between the V CC input
and the BAT output of the IC. The LTC4069 will continue
to operate at the reduced charge current until the input
supply voltage is increased or constant-voltage mode
reduces the charge current further.
Operation from Current Limited Wall Adapter
By using a current limited wall adapter as the input supply,
the LTC4069 dissipates significantly less power when pro-
grammed for a current higher than the limit of the supply
as compared to using a non-current limited supply at the
same charge current.
Consider a situation where an application demands a
600mA charge current for an 800mAh Li-Ion battery. If a
typical 5V (non-current limited) input supply is used, the
charger’s peak power dissipation can exceed 1W.
Now consider the same scenario, but with a 5V input
supply with a 600mA current limit. To take advantage
of the current limited supply, it is necessary to pro-
gram the LTC4069 to charge at a current above 600mA.
Assume that the LTC4069 is programmed for 750mA
(i.e., R PROG = 1.33k) to ensure that part tolerances main-
tain a programmed current higher than 600mA. Since the
LTC4069 will demand a charge current higher than the
current limit of the voltage supply, the supply voltage will
drop to the battery voltage plus 600mA times the “on”
resistance of the internal PFET. The “on” resistance of the
LTC4069 power device is approximately 450mΩ with a 5V
supply. The actual “on” resistance will be slightly higher
due to the fact that the input supply will drop to less than
5V. The power dissipated during this phase of charging
is less than 240mW. That is a 76% improvement over the
non-current limited supply power dissipation.
USB and Wall Adapter Power
Although the LTC4069 allows charging from a USB port,
a wall adapter can also be used to charge Li-Ion batteries.
Figure 4 shows an example of how to combine wall adapter
and USB power inputs. A P-channel MOSFET, MP1, is
used to prevent back conducting into the USB port when a
wall adapter is present and Schottky diode, D1, is used to
prevent USB power loss through the 1k pull-down resistor.
Typically a wall adapter can supply significantly more
current than the 500mA-limited USB port. Therefore, an
N-channel MOSFET, MN1, and an extra program resistor
are used to increase the charge current to 750mA when
the wall adapter is present.
Stability Considerations
The LTC4069 contains two control loops: constant-voltage
and constant-current. The constant-voltage loop is stable
without any compensation when a battery is connected
12
For more information www.linear.com/LTC4069
4069fc
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4069EDC-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Standalone 750mA Li-Ion Battery Charger in 2 × 2 DFN with NTC Thermistor Input |
| LTC4070 | 制造商:LINEAR 制造商全称:LINEAR 功能描述:Ultralow Voltage Step-Up Converter and Power Manager |
| LTC4070EDDB | 制造商:LINER 制造商全称:Linear Technology 功能描述:Li-Ion/Polymer Shunt Battery Charger System |
| LTC4070EDDB#PBF | 制造商:Linear Technology 功能描述:Battery Charger Li-Ion/Li-Pol 50mA 4.2V 10-Pin DFN EP Bulk 制造商:Linear Technology 功能描述:IC BATTERY CHARGER 50mA DFN-8 制造商:Linear Technology 功能描述:IC, BATTERY CHARGER, 50mA, DFN-8 制造商:Linear Technology 功能描述:IC, BATTERY CHARGER, 50mA, DFN-8; Battery Type:Li-Ion, Li-Polymer; Battery Charge Voltage:4.2V; Charge Current Max:50mA; Battery IC Case Style:DFN; No. of Pins:8; No. of Series Cells:1; Operating Temperature Min:-40C ;RoHS Compliant: Yes |
| LTC4070EDDB#TRMPBF | 功能描述:IC LI-ION/POLY BATT CHARGER 8DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 其它有关文件:STC3100 View All Specifications 特色产品:STC3100 - Battery Monitor IC 标准包装:4,000 系列:- 功能:燃料，电量检测计/监控器 电池化学:锂离子（Li-Ion） 电源电压:2.7 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-TSSOP，8-MSOP（0.118"，3.00mm 宽） 供应商设备封装:8-MiniSO 包装:带卷 (TR) 其它名称:497-10526-2 |
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