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參數(shù)資料
| 型號： | A8430 |
| 廠商： | Allegro MicroSystems, Inc. |
| 元件分類： | LED驅動器 |
| 英文描述： | White LED Driver Constant Current Step-up Converter |
| 中文描述： | 白光LED驅動恒流升壓轉換器 |
| 文件頁數(shù)： | 5/10頁 |
| 文件大小： | 329K |
| 代理商： | A8430 |
5
Worcester, Massachusetts 01615-0036 (508) 853-5000
115 Northeast Cutoff, Box 15036
www.allegromicro.com
D
2
A8430
White LED Driver Constant Current Step-up Converter
Device Operation
The A8430 uses a constant-frequency, current-mode control
scheme to regulate the current through the load. The load
current produces a voltage across the external sense resistor
(R1) and the input at the FB pin. This voltage is then
compared to the internal 95 mV reference to produce an error
signal. The switch current is sensed by the internal sense
resistor and compared to the load current error signal. As the
load current increases, the error signal diminishes, reducing
the maximum switch current and thus the current delivered
to the load. As
the load current
decreases, the error signal
rises, increasing the maximum switch current and thus
increasing the current delivered to the load.
To set
the load current,
ensure that the required internal
reference value of 95 mV is produced at the desired load. To
do so, select a resistance value for the sense resistor, R1 (
),
such that:
R1 = 95 mV
I
LOAD
where
I
LOAD
is the target load current (mA).
The table below shows typical values for R1. Note that the
resistance value is from the standard E96 series.
As load current is reduced, the energy required in the
inductor diminishes, resulting in the inductor current
dropping to zero for low load current levels. This is known
as Discontinuous mode operation, and results in some low-
frequency ripple. The average load current, however, remains
regulated down to zero.
In Discontinuous mode, when the inductor current drops to
zero, the voltage at the SW pin rings, due to the capacitance
in the resonant LC circuit formed by the inductor and the
capacitance of the switch and the diode. This ringing is
low-frequency and is not harmful. It can be damped with a
resistor across the inductor, but this reduces efficiency and is
not recommended.
Target Load Current
(
I
LOAD
)
(mA)
Sense Resistor (R1)
(
)
5
19.1
10
9.53
12
7.87
15
6.34
20
4.75
0
10
20
30
40
50
60
70
80
90
100
110
120
5
10
15
20
25
I
OUT
(mA)
P
Vin = 3V, 3 LED
Vin = 5V, 3 LED
Vin = 3V, 4 LED
Vin = 5V, 4 LED
Power Dissipation versus I
OUT
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| A8430EEK | White LED Driver Constant Current Step-up Converter |
| A8430EEK-T | White LED Driver Constant Current Step-up Converter |
| A8431 | White LED Driver Constant Current Step-up Converter |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| A8430EEK | 功能描述:IC LED DRVR WHITE BCKLGHT 5-MLPD RoHS:否 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(nèi)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 |
| A8430EEK-T | 制造商:ALLEGRO 制造商全稱:Allegro MicroSystems 功能描述:White LED Driver Constant Current Step-up Converter |
| A8430EEKTR-T | 功能描述:IC LED DRVR WHITE BCKLGHT 5-MLPD 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(nèi)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 |
| A8430EEKTR-T | 制造商:Allegro MicroSystems 功能描述:DC-DC Converter IC |
| A8431 | 制造商:ALLEGRO 制造商全稱:Allegro MicroSystems 功能描述:White LED Driver Constant Current Step-up Converter |
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