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參數(shù)資料
| 型號： | CAT4237TD |
| 英文描述： | High Voltage CMOS Boost White LED Driver |
| 中文描述： | 高電壓的CMOS升壓白光LED驅(qū)動器 |
| 文件頁數(shù)： | 4/13頁 |
| 文件大?。?/td> | 533K |
| 代理商： | CAT4237TD |
CAT4237
2005 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
4 of 13
Doc. No. 5013, Rev. A
DEVICE OPERATION
The CAT4237 is a fixed frequency (1MHz),
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 0.3V across
the feedback resistor connected to the
feedback pin (FB). The value of the resistor
sets the LED current accordingly (0.3V/R1).
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 40mA of load current into a
string of up to 8 white LEDs.
In the event of a “Open LED” fault condition,
where the feedback control loop becomes
open, the output voltage will continue to
increase. Once this voltage exceeds 35V, 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
μ
s and keep it on for about 1
μ
s
only.
Thermal overload protection circuitry has
been included to prevent the device from
operating at unsafe junction temperatures
above 150oC. In the event of a thermal
overload
condition
automatically shutdown and wait till the
junction temperatures cools to 130oC before
normal operation is resumed.
Light load operation
Under light load condition (under 4mA) and
with input voltage above 4.2V, the CAT4237
driving 6 LEDs, the driver starts pulse
skipping. Although the LED current remains
well regulated, some lower frequency ripple
may appear.
the
device
will
Switching Waveform VIN = 4.2V, I
LED
= 4mA
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| CAT4237TS | High Voltage CMOS Boost White LED Driver |
| CAT4240 | 6 Watt Boost LED Driver |
| CAT4240TD-GT3 | 6 Watt Boost LED Driver |
| CAT507BP | 3.3V 32K/64K x 16/18 Dual-Port Static RAM |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| CAT4237TD-26771T3 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Catalyst Semiconductor 功能描述: |
| CAT4237TD-GT3 | 功能描述:LED照明驅(qū)動器 LED Driver,Boost 8 LED,series RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
| CAT4237TD-GT3 | 制造商:ON Semiconductor 功能描述:IC, WHITE LED DRIVER, BOOST, TSOT-23-5 |
| CAT4237TD-T3 | 功能描述:LED照明驅(qū)動器 High Voltage Boost White LED RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
| CAT4237TS | 制造商:CATALYST 制造商全稱:Catalyst Semiconductor 功能描述:High Voltage CMOS Boost White LED Driver |
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