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參數(shù)資料
| 型號： | SP6683EU |
| 元件分類： | LED驅(qū)動(dòng)器 |
| 英文描述： | High Power LED Driver for Parallel Configuration |
| 中文描述： | 大功率并聯(lián)配置驅(qū)動(dòng)程序 |
| 文件頁數(shù)： | 4/10頁 |
| 文件大?。?/td> | 200K |
| 代理商： | SP6683EU |
4
Date: 07/07/04
SP6683 White LEDs Driver for Parallel Configuration Copyright 2004 Sipex Corporation
4) V
OUT
Comparator and Output Control.
A
306mV reference voltage is compared to feed-
back output voltage to control the Vout needed
for the application. Output current is set by a
bias resistor from FB pin to GND pin chosen by
the relationship:
I
OUT
= V
FB
R
FB
where V
FB
= 306mV.
Configuring the SP6683 as Voltage or
Current Source
The white LED load configuration used by
customers can be discrete white LEDs or a white
LED module. Inside the white LED module,
there may or may not be resistors in series with
the white LEDs. According to the different
application requirements, the SP6683 can be
configured as either a voltage source or a current
source to provide solutions for these different
applications, as shown in figure 9~12. Figure 9
shows using the SP6683 to drive discrete white-
LEDs as a current source.
The current in one white LED current is set by
the ratio of the feedback pin voltage (306mV)
and the bias resistor R
B
. To set the operating
current, R
B
can be selected by:
R
B
= V
FB
I
LED
The current of the remaining white LEDs is set
according to the similarity of the white LEDs. 3-
wire white LED module with internal series
resistors as shown in figure 10 can also be driven
1
8
5
Rb
SP6683
Rb
1uF
GND
FB
V
OUT
Figure 9. Driving discrete white LEDs as current source
General Overview
The SP6683 is a current regulated charge pump
ideal for converting a Li-Ion battery input for
driving white LEDs used in backlighting color
displays in cellular phones, PDAs, digital cam-
eras and MP3 players. The SP6683 is able to
efficiently drive up to eight 20mA white LEDs
in parallel and maintain a constant brightness
over a very wide operating voltage range (2.7V
to 5.5V). The SP6683 operates with an internal
nal components. Other features of SP6683 in-
clude PWM dimming control as well as com-
plete input/out disconnect in shutdown. In shut
down mode the IC draws less than 1.5
μ
A cur-
rent. The output regulation is achieved by sens-
ing the voltage at the feedback pin and modulat-
ing the switch between the charge pump and
output capacitor.
Theory of Operation
The SP6683 regulated charge pump block dia-
gram consists of four main blocks (Voltage
Reference, Mode Control, Clock Manager, Start-
up and Charge-Pump Switches) and two com-
parators (V
MODE
Comparator and V
OUT
Com-
parator).
1) Voltage Reference.
This block provides the
306mV and 1.25V reference voltages needed
for the two comparators.
2) Mode Control.
An external voltage divider
connected to the V
MODE
pin will define an input
voltage to the mode comparator which sets the
logic state of the mode selection outputs to the
X1 or X1.5 modes. V
MODE
is compared to a
1.25V bandgap voltage. For example, if one
makes a 158K/100K divider, the mode will
change at 2.58 x 1.25 V =3.23V. A comparator-
based cycle by cycle regulation ensures that no
mode change occurs during cycles.
3) Clock Manager.
An internal 1.2MHz clock
is generated in this block. Depending on the
mode control, the appropriate clock phasing is
generated here and sent to the start-up and
charge-pump switches block.
OPERATION
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| SP6685ERTR | Charge Pump LED Driver For Camera Flash |
| SP6685 | Charge Pump LED Driver For Camera Flash |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SP6683EU/TR | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:High Power LED Driver for Parallel Configuration |
| SP6683UEB | 功能描述:LED 照明開發(fā)工具 High Power LED Drvr for Parallel Config RoHS:否 制造商:Fairchild Semiconductor 產(chǎn)品:Evaluation Kits 用于:FL7732 核心: 電源電壓:120V 系列: 封裝: |
| SP6685 | 制造商:EXAR 制造商全稱:EXAR 功能描述:700mA Buck/Boost Charge Pump LED Driver |
| SP6685_06 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:700mA Buck/Boost Charge Pump LED Driver |
| SP6685EB | 功能描述:電源管理IC開發(fā)工具 Eval Board for SP6685 Series 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 |
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