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參數(shù)資料
| 型號： | ADP3522ACP-3 |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 電源管理 |
| 英文描述： | GSM Power Management System |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, QCC32 |
| 封裝： | 5 X 5 MM, EXPOSED PAD, MO-220-VHHD-2, LFCSP-32 |
| 文件頁數(shù)： | 18/20頁 |
| 文件大小： | 467K |
| 代理商： | ADP3522ACP-3 |
REV. 0
–18–
ADP3522
current is programmed by selecting the sense resistor, R1 (see
Figure 2).
The lithium ion charge current is calculated using
I
V
R
mV
R
1
CHR
SENSE
1
=
=
160
(5)
where
V
SENSE
is the high current limit threshold voltage. Or if
the charge current is known,
R
1 can be found:
R
V
I
mV
I
SENSE
CHR
CHR
1
160
=
=
(6)
Similarly the trickle charge current and the end of charge cur-
rent can be calculated:
I
V
R
mV
R
1
TRICKLE
SENSE
1
=
=
20
(7)
I
V
R
mV
R
1
EOC
SENSE
1
=
=
14
(8)
Example: Assume an 800 mA-H capacity lithium ion battery
and a 1 C charge rate.
R
1 = 200 m . Then
I
TRICKLE
= 100 mA
and
I
EOC
= 70 mA.
Appropriate sense resistors are available from the following
vendors:
Vishay Dale
IRC
Panasonic
Charger FET Selection
The type and size of the pass transistor is determined by the
threshold voltage, input-output voltage differential, and charge
current. The selected PMOS must satisfy the physical, electri-
cal, and thermal design requirements.
To ensure proper operation, the minimum VGS the ADP3522
can provide must be enough to turn on the FET. The available
gate drive voltage can be estimated using the following:
V
V
V
V
GS
ADAPTER MIN
GATEDR
SENSE
=
-
-
(
)
(9)
where
V
ADAPTER(MIN)
is the minimum adapter voltage.
V
GATEDR
is the gate drive “l(fā)ow” voltage, 0.5 V.
V
SENSE
is the maximum high current limit threshold voltage.
The difference between the adapter voltage (
V
ADAPTER
) and the
final battery voltage (
V
BAT
) must exceed the voltage drop due to
the blocking diode, the sense resistor, and the on resistance of
the FET at maximum charge current.
V
V
V
V
V
DS
ADAPTER
DIODE
SENSE
BAT
=
-
-
-
(10)
Then the
R
DS(ON)
of the FET can be calculated:
R
V
I
DS ON
(
DS
CHR MAX
(
)
)
=
(11)
The thermal characteristics of the FET must be considered
next. The worst-case dissipation can be determined using:
P
V
V
V
UVLO
I
DISS
ADAPTER MAX
×
DIODE
SENSE
CHR
=
(
)
(12)
It should be noted that the adapter voltage can be either
preregulated or nonregulated. In the preregulated case, the
difference between the maximum and minimum adapter voltage
is probably not significant. In the unregulated case, the adapter
voltage can have a wide range specified. However, the maxi-
mum voltage specified is usually with no load applied. So, the
worst-case power dissipation calculation will often lead to an
overspecified pass device. In either case, it is best to determine
the load characteristics of the adapter to optimize the charger
design.
For example:
V
ADAPTER(MIN)
= 5.0 V
V
ADAPTER(MAX)
= 6.5 V
V
DIODE
= 0.5 V at 800 mA
V
GATEDR
= 0.5 V
V
SENSE
= 160 mV
V
GS
= 5 V – 0.5 V – 0.160 V = 4.3 V. So choose a low
threshold voltage FET.
V
V
V
V
V
V
V
V
V
V
mV
DS
ADAPTER MIN
DIODE
SENSE
BAT
DS
=
-
-
-
=
-
-
-
=
(
)
.
.
.
5
0 5
0 160
4 2
140
(13)
R
V
I
mV
mA
m
DS ON
(
DS
CHR MAX
(
)
)
=
=
=
140
800
175
(14)
P
V
(
V
V
UVLO
I
P
×
V
.
V
V
V
A
W
DISS
ADAPTER MAX
×
DIODE
SENSE
CHR
DISS
0 8
=
=
=
)
(6 5
.
.
.
)
.
(
)
0 5
0 160
3 2
2 1
(15)
Appropriate PMOS FETs are available from the following vendors:
Siliconix
IR
Fairchild
Charger Diode Selection
The diode, D1, shown in Figure 2 is used to prevent the battery
from discharging through the PMOS’ body diode into the
charger’s internal bias circuits. A Schottky diode is recom-
mended to minimize the voltage difference from the charger to
the battery and the power dissipation. Choose a diode with a
current rating high enough to handle the battery charging cur-
rent and a voltage rating greater than VBAT. The blocking
diode is required for both lithium and nickel battery types.
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| ADP3522ACP-3-REEL | 制造商:Analog Devices 功能描述:GSM Power Management System 32-Pin LFCSP EP T/R |
| ADP3522ACP-3-REEL7 | 制造商:Analog Devices 功能描述:GSM Power Management System 32-Pin LFCSP EP T/R 制造商:Rochester Electronics LLC 功能描述: |
| ADP35622901 | 制造商:LG Corporation 功能描述:Fan Assembly,Propeller |
| ADP3603AR | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
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