- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄372190 > SP6683EU High Power LED Driver for Parallel Configuration PDF資料下載
參數(shù)資料
| 型號(hào)： | 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)： | 7/10頁 |
| 文件大小： | 200K |
| 代理商： | SP6683EU |
7
Date: 07/07/04
SP6683 White LEDs Driver for Parallel Configuration Copyright 2004 Sipex Corporation
APPLICATION INFORMATION: Continued
Since the brightness of the white LED is propor-
tional to the operating current, for better bright-
ness matching, a higher output voltage could be
used. This could be done by using larger resistor,
as shown in figure 14. Rb2 is used to bias the
operating current of the white LED, Rb1 is use to
increase the output voltage. Better brightness
matching was achived at the cost of the power
wasted on the bias resistor.
Power Efficiency
The efficiency of driving the white LEDs can be
calculated by
η
= V
F
I
F
= V
F
I
F
≈
V
F
V
i
I
i
V
i
(n I
F
+ I
Q
)
Where V
i
, I
i
are input voltage and current V
F
, I
F
are the forward voltage and operating current of
White LEDs I
Q
is quiescent current, which is
considered small compared with I
F
.
V
i
n
Rb1
8
V
FB
D1
Rb
Dn
GND
VFn
VF1
V
OUT
1
Rb2
VF2
Rb
5
D2
SP6683
I
1
I
2
I
n
Figure 14. Increasing brightness matching
Brightness Control Using PWM
Dimming control can be achieved by applying
a PWM contol signal to the EN/PWM pin. The
brightness of the white LEDs is controlled by
increasing and decreasing the duty cycle of the
PWM signal. While operating frequency range
is from 60Hz to 700Hz, the recomended
maxium brightness frequncy range is from
60Hz to 200Hz. A repition rate of at least 60Hz
is required to prevent flicker.
Brightness Matching
For white LEDs, the forward voltage drop is a
function of the operating current. However,
for a given current, the forward voltage drops
do not always match due to normal manufac-
turing tolerance, thus causing uneven bright-
ness of the white LEDs.
In figure 14, assume high-precision bias resis-
tors were used, the operating current ratio of
two different branches can be easily derived as
shown by:
I
1
= V
OUT
- V
F1
I
2
V
OUT
- V
F2
where I
1
I
2
are the operating current of the
white
LEDs,V
F1
,V
F2
are the forward voltage of the
white LEDs.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SP6685ERTR | Charge Pump LED Driver For Camera Flash |
| SP6685 | Charge Pump LED Driver For Camera Flash |
| SP6685ER | Charge Pump LED Driver For Camera Flash |
| SP6690 | Micro Power Boost Regulator Series White LED Driver |
| SP6690EB | Evaluation Board Manual |
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(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。