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| 型号： | LT1513-2IT7#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 7/16页 |
| 文件大小： | 0K |
| 描述： | IC BATT CHG CNST/PROG I/V TO2207 |
| 标准包装： | 50 |
| 功能： | 充电管理 |
| 电池化学： | 所有电池类型 |
| 电源电压： | 2.7 V ~ 25 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 通孔 |
| 封装/外壳： | TO-220-7 成形引线 |
| 供应商设备封装： | TO-220-7 |
| 包装： | 管件 |
LT1513/LT1513-2
APPLICATIO N S I N FOR M ATIO N
The LT1513 is an IC battery charger chip specifically opti-
mized to use the SEPIC converter topology. A complete
charger schematic is shown in Figure 1. The SEPIC topology
has unique advantages for battery charging. It will operate
with input voltages above, equal to or below the battery
voltage, has no path for battery discharge when turned off,
Figure 3. D2, C6 and R6 form a peak detector to drive the gate
of the FET to about the same as the battery voltage. If power
is turned off, the gate will drop to 0V and the only drain on the
battery will be the reverse leakage of the catch diode D1. See
Diode Selection for a discussion of diode leakage.
and eliminates the snubber losses of flyback designs. It also
ADAPTER
L1A
C2
D1
has a current sense point that is ground referred and need
INPUT
not be connected directly to the battery. The two inductors
shown are actually just two identical windings on one
inductor core, although two separate inductors can be used.
A current sense voltage is generated with respect to ground
across R3 in Figure 1. The average current through R3 is
V IN
LT1513
GND
V SW
V FB
L1B
R3
D2
C6
470pF
R6
470k
R1
R2
+
C1
always identical to the current delivered to the battery. The
LT1513 current limit loop will servo the voltage across R3
to – 100mV when the battery voltage is below the voltage
limit set by the output divider R1/R2. Constant-current
charging is therefore set at 100mV/R3. R4 and C4 filter the
SCHEMATIC SIMPLIFIED FOR CLARITY
D2 = 1N914, 1N4148 OR EQUIVALENT
Figure 3. Eliminating Divider Current
1513 F03
current signal to deliver a smooth feedback voltage to the I FB
pin. R1 and R2 form a divider for battery voltage sensing and
set the battery float voltage. The suggested value for R2 is
12.4k. R1 is calculated from:
Maximum Input Voltage
Maximum input voltage for the LT1513 is partly determined
by battery voltage. A SEPIC converter has a maximum
R 1 =
R2(V BAT – 1 .245)
1 . 245 + R 2 ( 0 . 3 μ A )
switch voltage equal to input voltage plus output voltage.
The LT1513 has a maximum input voltage of 30V and a
maximum switch voltage of 40V, so this limits maximum
V BAT = battery float voltage
0.3 μ A = typical FB pin bias current
A value of 12.4k for R2 sets divider current at 100 μ A. This is
a constant drain on the battery when power to the charger is
off. If this drain is too high, R2 can be increased to 41.2k,
reducing divider current to 30 μ A. This introduces an addi-
tional uncorrectable error to the constant voltage float mode
of about ± 0.5% as calculated by:
input voltage to 30V, or 40V – V BAT , whichever is less.
Shutdown and Synchronization
The dual function S/S pin provides easy shutdown and
synchronization. It is logic level compatible and can be
pulled high or left floating for normal operation. A logic low
on the S/S pin activates shutdown, reducing input supply
current to 12 μ A. To synchronize switching, drive the S/S pin
V BAT Error =
± 0.15 μ A(R1)(R2)
1.245(R1+ R2)
between 600kHz and 800kHz.
Inductor Selection
± 0.15 μ A = expected variation in FB bias current around the
nominal 0.3 μ A typical value.
With R2 = 41.2k and R1 = 228k, (V BAT = 8.2V), the error due
to variations in bias current would be ± 0.42%.
A second option is to disconnect the divider when charger
L1A and L1B are normally just two identical windings on one
core, although two separate inductors can be used. A typical
value is 10 μ H, which gives about 0.5A peak-to-peak induc-
tor current. Lower values will give higher ripple current,
which reduces maximum charging current. 5 μ H can be used
if charging currents are at least 20% lower than the values
power is off. This can be done with a small NFET as shown in
sn1513 1513fas
7
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT-1513-535-012 | 制造商:Carling Technologies 功能描述:LT-SERIES TOGGLE SWITCH - Bulk |
| LT-1513-710-012 | 制造商:Carling Technologies 功能描述:LT-SERIES TOGGLE SWITCH - Bulk |
| LT1513C | 制造商:LINER 制造商全称:Linear Technology 功能描述:SEPIC Constant- or Programmable-Current/ Constant-Voltage Battery Charger |
| LT1513CR | 功能描述:IC BATT CHRGR CONST/PROG I/V 7DD 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) |
| LT1513CR#PBF | 功能描述:IC BATT CHRGR CONST/PROG I/V 7DD 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 |
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