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参数资料
| 型号： | A6281EESTR-T |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 7/11页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVER PWM CONTROL 16-QFN |
| 产品培训模块： | A6281 Three-channel LED Driver |
| 标准包装： | 1,500 |
| 恒定电流： | 是 |
| 拓扑： | 线性，PWM |
| 输出数： | 3 |
| 内部驱动器： | 是 |
| 类型 - 次要： | RGB |
| 频率： | 5MHz |
| 电源电压： | 4.75 V ~ 17 V |
| 输出电压： | 1 V ~ 3 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WFQFN 裸露焊盘 |
| 供应商设备封装： | 16-QFN/MLP 裸露焊盘（3x3） |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 85°C |
| 产品目录页面： | 1141 (CN2011-ZH PDF) |
| 其它名称： | 620-1218-2 |
A6281
3-Channel Constant Current LED Driver
with Programmable PWM Control
The relationship of the PWM n value to the output duty cycle is
given in the following table:
Output Current Selection
The overall maximum current is set by the external resistor,
PWM n
0
1
2
...
1023
Duty Cycle
0/1024 (0 %)
2/1024
3/1024
...
1024/1024 (100 %)
R EXT , connected between the REXT and LGND pins. After
being set, the maximum current remains constant regardless of
the LED voltage variation, supply voltage variation, temperature,
or other circuit parameters. The maximum output current can be
calculated using the following equation:
When the brightness register is set to zero, the outputs remain off
for the duration of the PWM cycle for a 0% DC. When a bright-
ness register is set to 1023, the LED for that output remains on
(100% DC) when OEI is active and begins the PWM cycle. The
output remains on when the PWM counter rolls over and begins
a new count.
The PWM counter begins counting at zero and increments only
when the OEI pin is held low. When the PWM counter reaches
the count of 1024, the counter resets to zero and continues
incrementing. The counter resets to zero on a rising edge of OEI,
upon recovery from UVLO, or when powering up. Latching new
data into the brightness registers will not reset the PWM counter.
A free-running internal 800 kHz oscillator is the master clock
for the PWM counter. A programmable clock divider frequency
allows the PWM to be set at approximately at 200 kHz, 400 kHz,
or 800 kHz, or the PWM can be set to count on the rising edge
of the external CI signal. Bit assignments for the programmable
clock divider are shown in the following table:
I OUT (max) = 753.12 / R EXT .
The relationship of the value selected for R EXT and I OUT is
shown in figure 6.
Internal Linear Regulator
The A6281 has a built-in linear regulator. The regulator operates
from a supply voltage of 5.5 to 17 V. It allows the VIN pin of the
A6281 to connect to the same supply as the LEDs. This simpli-
fies board design by eliminating the need for a chip supply bus
and external voltage regulators. For 5 V supplies, connect VIN
to VREG externally. Note: When using 5 V supplies, ensure that
VIN does not exceed the absolute maximum rating of the VREG
pin (6 V).
The VREG pin is used by the internal linear regulator to connect
to a bypass capacitor. This pin is for internal use only and is not
150
140
130
120
110
7
0
1
0
1
Bits
8
0
0
1
1
Clock Mode
800 kHz
400 kHz
External (count on rising
edge of CI signal)
200 kHz
100
90
80
70
60
50
40
30
20
10
The total number of possible colors of an RGB pixel is over
1 billion. Refer to figure 4 for the mapping of shift register bits
0
5
15
25
35 45
R EXT (k Ω )
55
65
75
to latches.
B its
Figure 6. Output Current versus External Resistor, R EXT
0 1 2 3 4 5 6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
28
29
30 a
31
PWM Counter 0
PWM Counter 1
PWM Counter 2
Address “0” X b
Dot Correction
Register 0
Clock
Mode
X
Dot Correction
Register 1
X X X
Dot Correction
Register 2
X ATB c ATB c Address “1” X
a Selects
c Allegro
which word is written to: Dot Correction/Clock Mode selection or PWM counter. b X indicates “ Don’t Care.”
Test Bit (ATB). Reserved for Allegro internal testing. Always set to zero (0) in the application.
Figure 5. Register Configuration
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
7
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相关代理商/技术参数 |
参数描述 |
|---|---|
| A6281KIT | 制造商:Allegro MicroSystems 功能描述:EVALIATION KIT |
| A6282 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:16-Channel Constant-Current LED Driver |
| A6282AEESTR-T | 制造商:Allegro MicroSystems LLC 功能描述: |
| A6282AELPTR-T | 制造商:Allegro MicroSystems LLC 功能描述: |
| A6282EES-T | 制造商:Allegro MicroSystems 功能描述:LED DRIVER 16 CH CONST-CURRENT 制造商:Allegro MicroSystems 功能描述:LED DRIVER, 16 CH, CONST-CURRENT 制造商:Allegro MicroSystems 功能描述:LED DRIVER, 16 CH, CONST-CURRENT; Topology:Constant Current; No. of Outputs:16; Output Current:51.1mA; Output Voltage:12V; Driver Case Style:QFN; Input Voltage Min:3V; Input Voltage Max:5.5V; Switching Frequency:30MHz; Operating ;RoHS Compliant: Yes |
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