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参数资料
| 型号： | LT1769IGN |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 电源管理 |
| 英文描述： | Constant-Current/ Constant-Voltage 2A Battery Charger with Input Current Limiting |
| 中文描述： | 2-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO28 |
| 封装： | 0.150 INCH, PLASTIC, SSOP-28 |
| 文件页数： | 12/16页 |
| 文件大小： | 214K |
| 代理商： | LT1769IGN |
12
LT1769
APPLICATIO
S I
N
FOR
ATIO
U
W
U
Figure 5. Current Comparator for Initiating Float Time Out
NEGATIVE EDGE
TO TIMER
1769 F04
3.3V OR 5V
ADAPTER
OUTPUT
3
8
7
1
4
2
D1
1N4148
C1
0.1
μ
F
BAT
SENSE
R1*
1.6k
R
S1
0.05
R4
470k
R3
430k
R2
560k
LT1011
+
D2
1N4148
* TRIP CURRENT =
=
≈
270mA
R1(V
BAT
)
(R2 + R3)(R
S1
)
(1.6k)(8.4V)
(560k + 430k)(0.05
)
–
V
BAT
BAT
R
S3
200
R
S2
200
LT1769
I
BAT
R1
2.465 2000
)(
I
R2
2.465 2000
)(
I
I
LOW
HI
LOW
=
(
)
=
(
)
All battery chargers with fast charge rates require some
means to detect full charge in the battery and terminate the
high charge current. NiCd batteries are typically charged at
high current until a temperature rise or battery voltage
decrease is detected as an indication of near full charge.
The charging current is then reduced to a much lower
value and maintained as a constant trickle charge. An
intermediate “top off” current may also be used for a fixed
time period to reduce total charge time.
NiMH batteries are similar in chemistry to NiCd but have
two differences related to charging. First, the inflection
characteristic in battery voltage as full charge is approached
is not nearly as pronounced. This makes it more difficult
to use –dV/dt as an indicator of full charge, and an
increase in battery temperature is more often used with a
temperature sensor in the battery pack. Secondly, con-
stant trickle charge may not be recommended. Instead, a
moderate level of current is used on a pulse basis (
≈
1%
to 5% duty cycle) with the time-averaged value substitut-
ing for a constant low trickle. Please contact the Linear
Technology Applications department about charge termi-
nation circuits.
If overvoltage protection is needed, R3 and R4 can be cal-
culated according to the procedure described in Lithium-
Ion Charging section. The OVP pin should be grounded if
not used.
When a microprocessor DAC output is used to control
charge current, it must be capable of sinking current at a
compliance up to 2.5V if connected directly to the PROG pin.
Thermal Calculations
If the LT1769 is used for charging currents above 1A, a
thermal calculation should be done to ensure that junction
temperature will not exceed 125
°
C. Power dissipation in
the IC is caused by bias and driver current, switch resis-
tance and switch transition losses. The GN package, with
a thermal resistance of 35
°
C/W, can provide a full 2A
charging current in many situations. A graph is shown in
the Typical Performance Characteristics section.
For 1A full current, the current sense resistor (R
S1
) should
be increased to 0.1
so that enough signal (10mV) will be
across R
S1
at 0.1A trickle charge to keep charging current
accurate.
For a 2-level charger, R1 and R2 are found from:
Nickel-Cadmium and Nickel-Metal-Hydride Charging
The 2A Lithium-Ion Battery Charger shown in Figure 1 can
be modified to charge NiCd or NiMH batteries. For ex-
ample, if a 2-level charge is needed; 1A when Q1 is on and
100mA when Q1 is off.
Figure 6. 2-Level Charging
R2
5.49k
R1
49.3k
300
PROG
1
μ
F
Q1
LT1769
1769 F05
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1769IGN#PBF | 功能描述:IC CHARGER BATT CONST V/I 28SSOP 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) |
| LT1769IGN#TR | 功能描述:IC CHARGER BATT CONST V/I 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) |
| LT1769IGN#TRPBF | 功能描述:IC CHARGER BATT CONST V/I 28SSOP 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) |
| LT1775CQ5 | 制造商:Linear Technology 功能描述: |
| LT1776 | 制造商:LINER 制造商全称:Linear Technology 功能描述:50mA, 3V to 80V Low Dropout Micropower Linear Regulator |
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