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| 型号： | CAT4237TD-T3 |
| 厂商： | ON Semiconductor |
| 文件页数： | 4/12页 |
| 文件大小： | 0K |
| 描述： | IC LED DRVR WHITE BCKLGHT TSOT-5 |
| 标准包装： | 1 |
| 恒定电流： | 是 |
| 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： | 白色 LED |
| 频率： | 800kHz ~ 1.3MHz |
| 电源电压： | 2.8 V ~ 5.5 V |
| 输出电压： | 30V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | SOT-23-5 细型，TSOT-23-5 |
| 供应商设备封装： | TSOT-23-5 |
| 包装： | 标准包装 |
| 工作温度： | -40°C ~ 85°C |
| 产品目录页面： | 805 (CN2011-ZH PDF) |
| 其它名称： | CAT4237TD-T3DKR |
CAT4237
Block Diagram
V IN
33 m H
SW
C1
4.7 m F
1 MHz
Oscillator
Over Voltage
Protection
C2
0.22 m F
V REF
V IN
300 mV
Enable
–
+
A1
R C
+
–
A2
PWM &
Logic
Driver
N 1
LED
Current
SHDN
Thermal
Shutdown
& UVLO
C C
R S
GND
Current
Sense
FB
Figure 2. Block Diagram
R1
15 W
Device Operation
The CAT4237 is a fixed frequency (1 MHz), low noise,
inductive boost converter that provides a constant current
with excellent line and load regulation. The device uses a
high-voltage CMOS power switch between the SW pin and
ground to energize the inductor. When the switch is turned
off, the stored energy in the inductor is released into the load
via the Schottky diode.
The on/off duty cycle of the power switch is internally
adjusted and controlled to maintain a constant regulated
voltage of 0.3 V across the feedback resistor connected to the
feedback pin (FB). The value of the resistor sets the LED
current accordingly (0.3 V/R 1 ).
During the initial power-up stage, the duty cycle of the
internal power switch is limited to prevent excessive in-rush
currents and thereby provide a “soft-start” mode of
operation.
While in normal operation, the device can deliver up to
40 mA of load current into a string of up to 8 white LEDs.
In the event of an “Open LED” fault condition, where the
feedback control loop becomes open, the output voltage will
continue to increase. Once this voltage exceeds 35 V, an
internal protection circuit will become active and place the
device into a very low power safe operating mode where
only a small amount of power is transferred to the output.
This is achieved by pulsing the switch once every 60 m s and
keep it on for about 1 m s only.
Thermal overload protection circuitry has been included
to prevent the device from operating at unsafe junction
temperatures above 150 ° C. In the event of a thermal
overload condition the device will automatically shutdown
and wait till the junction temperatures cools to 130 ° C before
normal operation is resumed.
Light Load Operation
Under light load condition (under 4 mA) and with input
voltage above 4.2 V, the CAT4237 driving 6 LEDs, the
driver starts pulse skipping. Although the LED current
remains well regulated, some lower frequency ripple may
appear.
Figure 3. Switching Waveform V IN = 4.2 V,
I LED = 4 mA
http://onsemi.com
4
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相关代理商/技术参数 |
参数描述 |
|---|---|
| CAT4237TS | 制造商:CATALYST 制造商全称:Catalyst Semiconductor 功能描述:High Voltage CMOS Boost White LED Driver |
| CAT4237TS-TE7 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Catalyst Semiconductor 功能描述: |
| CAT4238 | 制造商:ONSEMI 制造商全称:ON Semiconductor 功能描述:High Efficiency 10 LED Boost Converter |
| CAT4238_07 | 制造商:CATALYST 制造商全称:Catalyst Semiconductor 功能描述:High Efficiency 10 LED Boost Converter |
| CAT4238AEVB | 功能描述:BOARD EVALUATION DPP CAT4238A RoHS:是 类别:编程器，开发系统 >> 评估板 - LED 驱动器 系列:* 标准包装:1 系列:PowerWise® 电流 - 输出 / 通道:20mA 输出及类型:1，非隔离 输出电压:17V 特点:可调光 输入电压:2.7 ~ 5.5 V 已供物品:板 已用 IC / 零件:LM3508 相关产品:LM3508TLX-ND - IC LED DRVR WHT BCKLGT 9USMDLM3508TLDKR-ND - IC LED DRVR WHT BCKLGT 9MICROSMDLM3508TLCT-ND - IC LED DRVR WHT BCKLGT 9MICROSMDLM3508TLTR-ND - IC LED DRVR WHT BCKLGT 9MICROSMD |
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