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参数资料
| 型号： | SC4509WLTRT |
| 厂商： | Semtech |
| 文件页数： | 6/15页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR WT/OLED BCKLT MLPD-8 |
| 标准包装： | 1 |
| 拓扑： | PWM，升压（升压） |
| 输出数： | 1 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光 |
| 类型 - 次要： | OLED，白色 LED |
| 频率： | 1MHz ~ 1.4MHz |
| 电源电压： | 2.7 V ~ 10 V |
| 输出电压： | 20V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | MLPD-8 |
| 供应商设备封装： | 8-MLPD（2x2） |
| 包装： | 标准包装 |
| 工作温度： | -40°C ~ 85°C |
| 其它名称： | SC4509WLDKR |
SC4509
POWER MANAGEMENT
PRELIMINARY
Block Diagram
SW
Internal Schottky
FB
VOUT
VIN
V REF
1.25V
199mV
PWM
OVP
EN/SS
Theory of Operation
∑ S
Ramp
Generator
1.2MHz
Oscillator
R
S
Q
GND
The SC4509 is a constant frequency PWM step-up regu-
lator IC designed to operate with an input voltage range
from 2.7V to 10V.
A maximum output voltage of 20V allows for up to ? ve LEDs
to be connected in series, providing even illumination by
passing the same output current through each LED.
Designed for a low 199mV, the feedback voltage has a
direct effect on the converter ef ? ciency. Because the volt-
age drop across the feedback resistor does not contribute
to the output power (LED brightness), the lower the feed-
back voltage, the higher the ef ? ciency. A 1.2MHz oscillator
frequency saves board space by reducing external compo-
nent sizes, making the SC4509 ideal for battery-operated
products.
The SC4509 can be con ? gured as a voltage regulated
boost converter or as a current-regulating boost converter
for driving white LEDs. The device is designed to be stable
without additional external components in both cases.
Over-Voltage Protection (OVP)
To prevent the output voltage from exceeding the maxi-
mum switch voltage rating (30V), an over-voltage protec-
tion circuit is integrated. As soon as the output voltage
exceeds the OVP threshold, the converter stops switching
and the output voltage starts to drop. When the output
voltage drops back below the OVP threshold, the convert-
er resumes operation. This sequence will repeat for as
long as is necessary.
Enable and PWM Dimming
The SC4509 provides the EN/SS pin to serve multiple
functions. Its main function is as an enable pin (active
high). It also can be used to control LED brightness
when a PWM signal (up to 10kHz) of varying duty cycle is
applied. A third function acts as a soft-start control. Soft
start can be implemented by ramping the voltage applied
to the pin at startup or by slowly increasing the PMW duty
cycle.
? 2007 Semtech Corp.
6
www.semtech.com
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC450ITS | 制造商:Semtech Corporation 功能描述: |
| SC450ITS.TRT | 制造商:SEMTECH 功能描述:I.C. |
| SC450ITS.TRTCUT | 制造商:Semtech Corporation 功能描述: |
| SC450ITSTRT | 制造商:Semtech Corporation 功能描述:DC DC Cntrlr Single-OUT PWM DC to DC Controller 3V to 30V Input 38-Pin TSSOP T/R |
| SC450R1X542 | 制造商:American Power Conversion Corp (APC by Schneider Electric) 功能描述:APC Smart-UPS 制造商:Schneider Electric 功能描述:SMARTUPS SC 450 W/NETWORK MANAGEMENT CARD - Bulk |
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