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參數(shù)資料
| 型號： | SP6691 |
| 元件分類： | LED驅(qū)動器 |
| 英文描述： | Micro Power Boost Regulator Series White LED Driver |
| 中文描述： | 微功率升壓穩(wěn)壓器系列白光LED驅(qū)動器 |
| 文件頁數(shù)： | 9/15頁 |
| 文件大?。?/td> | 253K |
| 代理商： | SP6691 |
9
Date: 5/25/04
SP6691 Micro Power Boost Regualtor, Series White LED Driver Copyright 2004 Sipex Corporation5
precision resistors are recommended. Table 3
below shows the R
b
selection for different white
LED currents. For example, to set the operating
current to be 20mA, R
b
is selected as 60.4
, as
shown in the schematic.
Table 3. Bias Resistor Selection
I
F
(mA)
5
10
12
15
20
R
b
(
)
243
121
102
80.6
60.4
Output Voltage Program
The SP6691 can be programmed as either a
voltage source or a current source. To program
the SP6691 as voltage source, the SP6691 re-
quires 2 feedback resistors R
1
& R
2
to control
the output voltage. As shown in Figure 22.
Table 4. Divider Resistor Selection
V
OUT
(V)
12
15
18
21
30
R
1
(
)
1M
1M
1M
1M
1M
R
2
(
)
113K
88.7K
73.2K
61.9K
42.2K
Brightness Control
Dimming control can be achieved by applying a
PWM control signal to the SHDN pin. The
brightness of the white LEDs is controlled by
increasing and decreasing the duty cycle of the
PWM signal. A 0% duty cycle corresponds to
zero LED current and a 100% duty cycle corre-
sponds to full load current. While the operating
frequency range of the PWM control is from
60Hz to 700Hz, the recommended maximum
brightness frequency range of the PWM signal
is from 60Hz to 200Hz. A repetition rate of at
least 60Hz is required to prevent flicker. The
magnitude of the PWM signal should be higher
than the minimum SHDN voltage high.
Open Circuit Protection
When any white LED inside the white LED
module fails or the LED module is disconnected
from the circuit, the output and the feedback
control will be open, thus resulting in a high
output voltage, which may cause the SW pin
voltage to exceed it maximum rating. In this
case, a zener diode can be used at the output to
limit the voltage on the SW pin and protect the
part. The zener voltage should be larger than the
maximum forward voltage of the White LED
module.
APPLICATION INFORMAMTION: Continued
L1
1.22V
R2
D1
C1
C2
R1
VOUT
U1
SP6691
1
2
4
5
SW
GND
FB
SHDN
V
IN
VIN
Figure 22. Using SP6691 as Voltage Source
The formula and table for the resistor selection
are shown below:
R
=
(
V
OUT
- 1
)
R
2
1.22
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|---|---|
| SP6691_07 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:SOT23Micro Power Boost Regulator Series White LED Driver |
| SP6691EB | 功能描述:電源管理IC開發(fā)工具 Micro Pwr Boost Reg White LED Driver RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| SP6691EK | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:SOT23Micro Power Boost Regulator Series White LED Driver |
| SP6691EK/TR | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:SOT23Micro Power Boost Regulator Series White LED Driver |
| SP6691EK1 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:SOT23Micro Power Boost Regulator Series White LED Driver |
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