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参数资料
| 型号： | LT3497EDDB#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 12/20页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVR WHITE BCKLGT 10-DFN |
| 标准包装： | 2,500 |
| 拓扑： | PWM，升压（升压） |
| 输出数： | 2 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 1.8MHz ~ 2.8MHz |
| 电源电压： | 2.5 V ~ 10 V |
| 输出电压： | 35V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-WFDFN 裸露焊盘 |
| 供应商设备封装： | 10-DFN-EP（3x2） |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 85°C |
LT3497
APPLICATIONS INFORMATION
converter turns off. The MOSFETs ensure that the LEDs
quickly turn off without discharging the output capacitors
which in turn allows the LEDs to turn on faster. Figures 7
and 8 show the PWM dimming waveforms and ef?ciency
for the Figure 6 circuit.
The time it takes for the LEDs current to reach its pro-
grammed value sets the achievable dimming range for a
given PWM frequency. For example, the settling time of
the LEDs current in Figure 7 is approximately 40μs for a
3V input voltage. The achievable dimming range for this
application and 100Hz PWM frequency can be determined
using the following method.
Example:
? = 100Hz, t SETTLE = 40μs
t PERIOD = 1/? = 1/100 = 0.01s
Dim Range = t PERIOD /t SETTLE = 0.01s/40μs = 250:1
Min Duty Cycle = t SETTLE /t PERIOD ? 100
= 40μs/0.01s = 0.4%
Duty Cycle Range = 100% → 0.4% at 100Hz
The calculations show that for a 100Hz signal the dimming
range is 250 to 1. In addition, the minimum PWM duty
cycle of 0.4% ensures that the LEDs current has enough
3V TO 5V
1 μ F
L1
15 μ H
L2
15 μ H
SW1
CAP1
V IN
SW2
CAP2
1 μ F
R SENSE1
10 ?
LT3497
R SENSE2
10 ?
1 μ F
LED1 LED2
CTRL1 GND CTRL2
Q1
Si2318DS
Q2
Si2318DS
100k
5V
5V
100k
0V
PWM
PWM
0V
3497 F06
FREQ
FREQ
Figure 6. Li-Ion to 4/4 White LEDs with Direct PWM Dimming
I LED
20mA/DIV
I L
200mA/DIV
PWM
5V/DIV
80
78
76
74
V IN = 3.6V
4/4 LEDs
V IN = 3.6V
2ms/DIV
3497 F07
72
4 LEDs
Figure 7. Direct PWM Dimming Waveforms
70
0
5
10
15
20
LED CURRENT (mA)
3497 F08
Figure 8. Ef?ciency
3497f
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3498 | 制造商:LINER 制造商全称:Linear Technology 功能描述:20mA LED Driver and OLED Driver with Integrated Schottky in 3mm x 2mm DFN |
| LT3498EDDB | 制造商:LINER 制造商全称:Linear Technology 功能描述:20mA LED Driver and OLED Driver with Integrated Schottky in 3mm x 2mm DFN |
| LT3498EDDB#TRMPBF | 功能描述:IC LED DRVR WT/OLED BCKLGT 12DFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极，PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
| LT3498EDDB#TRPBF | 功能描述:IC LED DRVR WT/OLED BCKLGT 12DFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极，PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
| LT34-SC | 制造商:THOMAS & BETTS 功能描述: |
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