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参数资料
| 型号： | LTC4069EDC-4.4#TRMPBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO6 |
| 封装： | 2 X 2 MM, LEAD FREE, PLASTIC, MO-229WCCD-2, DFN-6 |
| 文件页数： | 4/16页 |
| 文件大小： | 192K |
| 代理商： | LTC4069EDC-4.4#TRMPBF |
12
LTC4069-4.4
406944f
tain a programmed current higher than 600mA. Since the
LTC4069-4.4 will demand a charge current higher than the
current limit of the input 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
LTC4069-4.4 power device is approximately 450m
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 charg-
ing is less than 180mW. That is a 82% improvement over
the non-current limited supply power dissipation.
USB and Wall Adapter Power
Although the LTC4069-4.4 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 LTC4069-4.4 contains two control loops: constant-
voltage and constant-current. The constant-voltage loop
is stable without any compensation when a battery is
connected with low impedance leads. Excessive lead
length, however, may add enough series inductance to
require a bypass capacitor of at least 1
F from BAT to
GND. Furthermore, a 4.7
F capacitor with a 0.2 to 1
series resistor from BAT to GND is required to keep ripple
voltage low when the battery is disconnected.
High value capacitors with very low ESR (especially ce-
ramic) may reduce the constant-voltage loop phase mar-
gin. Ceramic capacitors up to 22
F may be used in parallel
with a battery, but larger ceramics should be decoupled
with 0.2
to 1 of series resistance.
In constant-current mode, the PROG pin is in the feedback
loop, not the battery. Because of the additional pole
created by the PROG pin capacitance, 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 25k. However, addi-
tional capacitance on this node reduces the maximum
allowed program resistor. The pole frequency at the PROG
pin should be kept above 100kHz. Therefore, if the PROG
pin is loaded with a capacitance, CPROG, the following
equation should be used to calculate the maximum resis-
tance value for RPROG:
R
C
PROG
≤
π
1
2105
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
Figure 5. Isolating Capacitive Load on the PROG Pin and Filtering
APPLICATIO S I FOR ATIO
WU
UU
Figure 4. Combining Wall Adapter and USB Power
VCC
MP1
MN1
1k
2k
4.02k
ICHG
D1
Li-Ion
BATTERY
SYSTEM
LOAD
4069 F04
LTC4069-4.4
BAT
USB
POWER
500mA
ICHG
5V WALL
ADAPTER
750mA
ICHG
PROG
+
4069 F05
CFILTER
CHARGE
CURRENT
MONITOR
CIRCUITRY
RPROG
LTC4069-4.4
PROG
GND
10k
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4069EDC-PBF | 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 |
| 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 |
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