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参数资料
| 型号： | LT1769 |
| 厂商： | Linear Technology Corporation |
| 英文描述： | Constant-Current/ Constant-Voltage 2A Battery Charger with Input Current Limiting |
| 中文描述： | 恒流/恒压电池充电器，带甲输入限流 |
| 文件页数： | 13/16页 |
| 文件大小： | 214K |
| 代理商： | LT1769 |
13
LT1769
APPLICATIO
S I
FOR
ATIO
U
=
(
+
(
[
W
U
U
Figure 7. Lower V
BOOST
For example, V
X
= 3.3V then:
Then P
DRIVER
=
(
)(
)( )
(
V
IN
55
+
)
I
V
V
V
30
BAT
BAT
X
X
1
Total Power in the IC is: 0.35 + 0.43 + 0.5 = 1.3W
Temperature rise will be (1.3W)(35
°
C/W) = 46
°
C. This
assumes that the LT1769 is properly heat sunk by con-
necting the eleven fused ground pins to expanded traces
and that the PC board has a backside or internal plane for
heat spreading.
The P
DRIVER
term can be reduced by connecting the boost
diode D2 (see Figure 7) to a lower system voltage (lower
than V
BAT
) instead of V
BAT
.
SW
BOOST
SPIN
1769 F07
LT1769
V
X
I
VX
C2
D2
10
μ
F
L1
+
P
A
V
V
V
V
W
DRIVER
=
( )(
)(
)
)
+
(
=
2
12 6
3 3
.
1
3 3
30
55 19
0 09
.
.
.
The average I
VX
required is:
P
V
X
W
V
mA
DRIVER
=
=
0 09
3 3
28
.
.
The previous example shows the dramatic drop in driver
power dissipation when the boost diode (D2) is connected
to an external 3.3V source instead of the 12.6V battery.
P
DRIVER
drops from 0.43W to 0.09W resulting in an
approximately 12
°
C drop in junction temperature.
Fused-lead packages conduct most of their heat out the
leads. This makes it very important to provide as much PC
board copper around the leads as is practical. Total
thermal resistance of the package-board combination is
dominated by the characteristics of the board in the
immediate area of the package. This means both lateral
thermal resistance across the board and vertical thermal
resistance through the board to other copper layers. Each
layer acts as a thermal heat spreader that increases the
heat sinking effectiveness of extended areas of the board.
Total board area becomes an important factor when the
area of the board drops below about 20 square inches. The
graph in Figure 8 shows thermal resistance vs board area
for 2-layer and 4-layer boards with continuous copper
planes. Note that 4-layer boards have significantly lower
thermal resistance, but both types show a rapid increase
for reduced board areas. Figure 9 shows actual measured
lead temperatures for chargers operating at full current.
P
3.5mA V
1.5mA V
V
V
7.5mA
0.012 I
P
I
V
55 V
)(
P
I
R
V
V
t
V
I
f
BIAS
IN
BAT
BAT
2
IN
BAT
DRIVER
BAT
BAT
2
IN
SW
BAT
2
SW
BAT
IN
OL
IN
BAT
)
)
+
)
+
(
)
]
=
(
)(
)
+
)
)
+
(
=
(
) (
)(
)(
)( )
1
30
V
BAT
P
+
(
3.5mA 19
1.5mA 12.6
12.6
19
7.5mA
0.012 2000mA
)(
)
+
0.35W
P
( )(
55 19
)(
0.43W
P
2
0.16 12.6
19
10
19 2 200kHz
( )( )(
0.42 0.08
0.5W
BIAS
2
DRIVER
2
SW
2
9
=
(
+
)
)
+
(
)
)
[
]
=
=
+
=
=
( ) (
)
=
=
1
12 6
30
.
R
SW
= Switch ON resistance
≈
0.16
t
OL
= Effective switch overlap time
≈
10ns
f = 200kHz
Example: V
IN
= 19V, V
BAT
= 12.6V, I
BAT
= 2A:
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|---|---|
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1769CFE | 功能描述:IC BATT CHRGR CNSTNT I/V 20TSSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 功能:电池监控器 电池化学:碱性，锂离子，镍镉，镍金属氢化物 电源电压:1 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-6 包装:带卷 (TR) |
| LT1769CFE#PBF | 功能描述:IC BATT CHRGR CNSTNT I/V 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 功能:电池监控器 电池化学:碱性，锂离子，镍镉，镍金属氢化物 电源电压:1 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-6 包装:带卷 (TR) |
| LT1769CFE#TR | 功能描述:IC BATT CHRGR CNSTNT I/V 20TSSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 功能:电池监控器 电池化学:碱性，锂离子，镍镉，镍金属氢化物 电源电压:1 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-6 包装:带卷 (TR) |
| LT1769CFE#TRPBF | 功能描述:IC BATT CHRGR CNSTNT I/V 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 功能:电池监控器 电池化学:碱性，锂离子，镍镉，镍金属氢化物 电源电压:1 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-6 包装:带卷 (TR) |
| LT1769CGN | 功能描述:IC BATT CHARGER CONST I/V 28SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 功能:电池监控器 电池化学:碱性，锂离子，镍镉，镍金属氢化物 电源电压:1 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-6 包装:带卷 (TR) |
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