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參數(shù)資料
| 型號： | LM3520 |
| 廠商： | National Semiconductor Corporation |
| 元件分類： | LED驅動器 |
| 英文描述： | Integrated White LED Driver with Organic LED Display Power Supply |
| 中文描述： | 集成白光LED有機LED顯示屏驅動電源 |
| 文件頁數(shù)： | 12/14頁 |
| 文件大?。?/td> | 963K |
| 代理商： | LM3520 |
Application Information
(Continued)
The above equation to solve for R
SUB1
.
R
SUB1
= (V
SUB
/V
SUB_FB
– 1)R
SUB2
The LM3520 is optimized for 20V at 30 mA over the input
voltage range, for higher output current up to 50mA is
achieveable with a minimum input of 3.6V. If lower V
SUB
is
desired, the output current capability will be higher.
(3)
Using V
SUB
in Current Mode Configuration
If V
is used to drive a string of LEDs, instead of using
figure 3 configuration (voltage mode). The LEDs can be
arranged in current mode configuration to control load cur-
rent.
MAIN & SUB ENABLE
The LM3520 has two independent enable pins to control the
main and sub displays. A high on the Main Enable signal will
enable the main display. While a high on the Sub Enable pin
will enable the sub display. The PFM_EN pin must tied to
SUB_EN for enabling the Sub display. Both Main & Sub
enable pins should not be ON at the same time during
normal operation. If for any reason, the main and Sub enable
are high, the main display will enable by default and the sub
display will disable by default. The following truth table sum-
marize the logic state.
TABLE 1.
Main_EN
0
0
1
1
Sub_EN
0
1
0
1
Main
OFF
OFF
ON
ON
Sub
OFF
ON
OFF
OFF
INDUCTOR SELECTION
The inductor used with LM3520 must have a saturation
current greater than the device switch peak current limit.
Choosing inductors with low DCR decreases power losses
and increases efficiency. A 10 μH inductor is optimal for the
applications. If a smaller inductor is used, the larger the
inductor ripple current. Care must be taken to select the
inductor such that the peak current rating of the inductor
accounts for maximum load current for the operating condi-
tion. It is best to select an inductor with a peak current rating
of the maximum switch peak current of the device. The
following equation is useful for determining the inductor
value for a given application condition. Where I
=
maximum output load current, V
OUT
= output voltage, V
IN-
_MIN
= minimum input voltage, V
DIODE
= diode forward volt-
age, I
= Peak Current and f
max
= maximum switch fre-
quency.
TABLE 2.
Suppliers
Coilcraft
Cooper Bussmann
Murata
Website
www.coilcraft.com
www.cooperET.com
www.murata.com
DIODE SELECTION
To maintain high efficiency, the average current rating of the
schottky diode should be larger than the peak inductor cur-
rent. Schottky diodes with a low forward drop and fast
switching speeds are ideal for increasing efficiency in por-
table applications. Choose a reverse breakdown of the
schottky diode larger than the output voltage. Some recom-
mended diodes are MBR0530T1 from ON semiconductor
and CMMSHI-40 from Central Semiconductor.
CAPACITOR SELECTION
Choose low ESR capacitors for the output to minimize output
voltage ripple. Ceramic capacitors such as X5R and X7R are
recommended for use as input and output filiters. These
capacitors provide an ideal balance between small size,
cost, reliability and performance. Do not use Y5V ceramic
capacitors as they have poor dielectric performance over
temperature and poor voltage characteristic for a given
value. For most applications, a 1 μF ceramic output capaci-
20128805
FIGURE 4.
20128801
FIGURE 5.
L
www.national.com
12
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LM3520_0509 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Integrated White LED Driver with Organic LED Display Power Supply |
| LM3520B WAF | 制造商:Texas Instruments 功能描述: |
| LM3520SD | 制造商:Texas Instruments 功能描述:WLED/OLED DRIVER POWERWISE LLP-14 |
| LM3520SD | 制造商:Texas Instruments 功能描述:IC WLED/DISPLAY DRIVER POWERWISE |
| LM3520SD/NOPB | 功能描述:IC LED DRVR WT/OLED BCKLGT 14LLP RoHS:是 類別:集成電路 (IC) >> PMIC - LED 驅動器 系列:- 標準包裝:1 系列:- 恒定電流:- 恒定電壓:- 拓撲:PWM，切換式電容器（充電泵） 輸出數(shù):1 內部驅動器:是 類型 - 主要:背光 類型 - 次要:白色 LED 頻率:642kHz 電源電壓:2.7 V ~ 5.5 V 輸出電壓:5V 安裝類型:表面貼裝 封裝/外殼:10-VFDFN 裸露焊盤 供應商設備封裝:10-VSON 包裝:剪切帶 (CT) 工作溫度:-30°C ~ 85°C 產(chǎn)品目錄頁面:1371 (CN2011-ZH PDF) 其它名稱:BD1603NUV-E2CT |
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