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參數(shù)資料
| 型號： | SP6683 |
| 元件分類： | LED驅(qū)動器 |
| 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)動程序 |
| 文件頁數(shù)： | 7/10頁 |
| 文件大?。?/td> | 200K |
| 代理商： | SP6683 |
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
Rb
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.
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PDF描述 |
|---|---|
| SP6683ER | High Power LED Driver for Parallel Configuration |
| SP6683EU | High Power LED Driver for Parallel Configuration |
| 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 |
|---|---|
| SP6683EB | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Evaluation Board Manual |
| SP6683ER | 制造商:Exar Corporation 功能描述:Driver, Other |
| SP6683ER/TR | 功能描述:LED照明驅(qū)動器 High Power Parallel Configuration 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 |
| SP6683ER-L | 功能描述:LED照明驅(qū)動器 Configuration 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 |
| SP6683ER-L/TR | 功能描述:LED照明驅(qū)動器 High Power Parallel Configuration 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 |
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