参数资料
| 型号： | LTC4081EDD#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 17/24页 |
| 文件大小： | 0K |
| 描述： | IC USB POWER MANAGER 10-DFN |
| 标准包装： | 2,500 |
| 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： | 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： | 10-WFDFN 裸露焊盘 |
| 供应商设备封装： | 10-DFN（3x3） |
| 包装： | 带卷 (TR) |
LTC4081
APPLICATIO S I FOR ATIO
= V
? 1 ?
P D _ BUCK OUT OUT ?
Operation from Current Limited Wall Adapter
By using a current limited wall adapter as the input sup-
ply, the LTC4081 can dissipate signi?cantly less power
when programmed for a current higher than the limit of
the wall adapter.
Consider a situation where an application requires a 200mA
charge current for a discharged 800mAh Li-Ion battery.
If a typical 5V (non-current limited) input supply is avail-
able then the peak power dissipation inside the part can
exceed 300mW.
Now consider the same scenario, but with a 5V input
supply with a 200mA current limit. To take advantage
of the supply, it is necessary to program the LTC4081
to charge at a current greater than 200mA. Assume that
the LTC4081 charger is programmed for 300mA (i.e.,
R PROG = 1.33k Ω ) to ensure that part tolerances maintain
a programmed current higher than 200mA. Since the
battery charger will demand a charge current higher than
the current limit of the input supply, the supply voltage
will collapse to the battery voltage plus 200mA times the
on-resistance of the internal PFET. The on-resistance of
the battery charger power device is approximately 0.7 Ω
with a 5V supply. The actual on-resistance will be slightly
higher due to the fact that the input supply will have col-
lapsed to less than 5V. The power dissipated during this
phase of charging is approximately 30mW. That is a ten
times improvement over the non-current limited supply
power dissipation.
USB and Wall Adapter Power
Although the LTC4081 allows charging from a USB port,
a wall adapter can also be used to charge Li-Ion batter-
ies. 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
pulldown resistor.
Typically a wall adapter can supply signi?cantly more
current than the current-limited USB port. Therefore, an
N-channel MOSFET, MN1, and an extra program resistor
can be used to increase the charge current when the wall
adapter is present.
Power Dissipation
The conditions that cause the LTC4081 battery charger to
reduce charge current through thermal feedback can be
approximated by considering the total power dissipated
in the IC. For high charge currents, the LTC4081 power
dissipation is approximately:
P D = ( V CC ? V BAT ) ? I BAT + P D _ BUCK
Where P D is the total power dissipated within the IC, V CC
is the input supply voltage, V BAT is the battery voltage, I BAT
is the charge current and P D_BUCK is the power dissipation
due to the regulator. P D_BUCK can be calculated as:
? 1 ?
? I
? η ?
5V WALL
ADAPTER
(500mA)
D1
BAT
1
I CHG
SYSTEM
LOAD
USB
POWER
(100mA)
MP1
2
LTC4081
V CC
PROG
4
+
Li-Ion
BATTERY
MN1 1k
4k
1k
4081 F04
Figure 4. Combining Wall Adapter and USB Power
4081f
17
相关PDF资料 |
PDF描述 |
|---|---|
| LTC4085EDE#TRPBF | IC USB POWER MANAGER 14-DFN |
| LTC4088EDE#TRPBF | IC BATT CHARGER/USB 14-DFN |
| LTC4089EDJC-5#TRPBF | IC USB POWER MANAGER 22-DFN |
| LTC4090EDJC-5#TRPBF | IC USB POWER MANAGER 22-DFN |
| LTC4095EDC#TRPBF | IC CHARGER LI-ION/POLY 8-DFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4085 | 制造商:LINER 制造商全称:Linear Technology 功能描述:High Efficiency Battery Charger/USB Power Manager |
| LTC4085-1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:USB Power Manager with Ideal Diode Controller and 4.1V Li-Ion Charger |
| LTC4085-3 | 制造商:LINER 制造商全称:Linear Technology 功能描述:USB Power Manager with Ideal Diode Controller and 3.95V Li-Ion Charger |
| LTC4085EDE | 制造商:Linear Technology 功能描述:USB Power Manager 14-Pin DFN EP |
| LTC4085EDE#PBF | 功能描述:IC USB POWER MANAGER 14-DFN 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 |
发布紧急采购，3分钟左右您将得到回复。