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EUP2584AVIR1 参数 Datasheet PDF下载

EUP2584AVIR1图片预览
型号: EUP2584AVIR1
PDF下载: 下载PDF文件 查看货源
内容描述: 白光LED升压型转换器采用微型SOT- 23封装 [White LED Step-Up Converter In Tiny SOT-23 Package]
分类和应用: 转换器
文件页数/大小: 11 页 / 420 K
品牌: EUTECH [ EUTECH MICROELECTRONICS INC ]
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EUP2584A  
Constant Output Voltage for Backlight of Main  
Panel and Flashlight  
Constant Output Voltage for Backlight of Main  
Panel and Keypad  
Figure 6 is an application of EUP2584A for backlight  
of main panel and flashlight. Setting the  
divider-resistors (R1 & R2) is to get a constant output  
voltage that depends on the forward voltage and the  
numbers of series-LEDs. There are three kinds of mode  
controlled by the switches - backlight mode /flashlight  
mode /backlight + flashlight mode. It can turn on  
backlight or flashlight at one time or both at the same  
time. Applying different duty cycle of PWM signal  
above 22kHz to backlight's switch can also control the  
brightness. The following formula (2)(3) can determine  
R3 and R4.  
Figure 7 is another application of EUP2584A for  
backlight and keypad. Setting the divider-resistors (R1  
& R2) is to get a constant output voltage that depends  
on the forward voltage and the numbers of series-LEDs.  
It can turn on backlight of main panel and keypad at  
the same time. Applying different duty cycle of PWM  
signal above 22kHz to the backlight's switch can also  
control the brightness of main panel's backlight. The  
keypad's backlight will keep the same brightness  
during the dimming control of main panel. Otherwise  
the brightness of keypad's s backlight can also change  
during the dimming control of main panel by using the  
application circuit as figure 4. The following formula  
(5)(6) can determine the resistors of Figure 8.  
V
3VFb V  
OUT  
DS  
R3 =  
R4 =  
--------------------------(2)  
--------------------------(3)  
Ib  
V
3VFb V  
OUT  
DS  
V
3VFf V  
R3 =  
----------------------------(5)  
OUT  
DS  
Ib  
If  
V
3VFk  
V
= Ib×R  
---------------------------------(4)  
DS(ON)  
OUT  
DS  
R4 = R5 = R6 =  
= Ib×R  
----------------------(6)  
Ik  
----------------------------------(7)  
DS(ON)  
V
DS  
Figure 6. Constant Output Voltage for Backlight and Flashlight  
Figure 7. Constant Output Voltage for Backlight and Keypad  
DS2584A Ver1.0 Nov. 2007  
10